$AIZ
ASSURANT, INC. Stock $aiz

$aiz Overview Financials Valuation SEC Filings Company Website

2021 Q4 Form 10-K Financial Statement

#000126723822000006 Filed on February 22, 2022

Income Statement

Concept	2021 Q4	2021 Q3	2021
Revenue	$2.575B	$2.638B	$10.19B
YoY Change	6.48%	10.99%	6.17%
Cost Of Revenue		$614.2M	$2.196B
YoY Change		-3.81%	-3.06%
Gross Profit		$2.024B	$7.992B
YoY Change		16.42%	9.02%
Gross Profit Margin		76.72%	78.45%
Selling, General & Admin	$939.4M	$818.3M	$3.241B
YoY Change	20.71%	21.61%	6.32%
% of Gross Profit		40.44%	40.55%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$45.60M	$41.90M	$73.80M
YoY Change	16.33%	4.49%	31.55%
% of Gross Profit		2.07%	0.92%
Operating Expenses	$2.386B	$818.3M	$3.241B
YoY Change	1.75%	21.61%	6.32%
Operating Profit		$1.205B	$4.751B
YoY Change		13.14%	10.94%
Interest Expense	-$27.10M	$27.50M	$111.8M
YoY Change	1.12%	7.84%	6.99%
% of Operating Profit		2.28%	2.35%
Other Income/Expense, Net
YoY Change
Pretax Income	$161.8M	$191.5M	$783.0M
YoY Change	1.83%	70.22%	34.81%
Income Tax	$35.10M	$37.90M	$169.5M
% Of Pretax Income	21.69%	19.79%	21.65%
Net Earnings	$123.6M	$882.4M	$1.372B
YoY Change	-11.21%	-3021.85%	210.64%
Net Earnings / Revenue	4.8%	33.45%	13.47%
Basic Earnings Per Share	$2.16	$14.92	$23.13
Diluted Earnings Per Share	$2.14	$14.83	$22.83
COMMON SHARES
Basic Shares Outstanding	56.98M shares	59.13M shares	59.14M shares
Diluted Shares Outstanding		59.48M shares	60.12M shares

Balance Sheet

Concept	2021 Q4	2021 Q3	2021
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$2.041B	$2.028B	$2.041B
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$561.4M	$529.0M	$561.4M
YoY Change	25.85%	12.94%	0.25%
Goodwill	$2.572B	$2.580B
YoY Change	-0.68%	10.93%
Intangibles	$719.2M	$638.4M
YoY Change	3.3%	9.73%
Long-Term Investments	$8.672B	$9.197B	$8.672B
YoY Change	-44.69%	-39.52%	-44.69%
Other Assets	$1.077B	$0.00	$1.077B
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$33.92B	$33.62B	$33.92B
YoY Change	-24.03%	-22.85%	-24.03%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$3.044B	$2.574B	$3.044B
YoY Change	8.92%	2.89%	8.92%
Accrued Expenses			$60.50M
YoY Change			-22.44%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$5.342B	$5.136B	$5.342B
YoY Change	-14.41%	-11.55%	-14.41%
LONG-TERM LIABILITIES
Long-Term Debt	$2.203B	$2.202B	$2.203B
YoY Change	1.26%	9.6%	1.26%
Other Long-Term Liabilities	$1.065B	$0.00	$1.065B
YoY Change
Total Long-Term Liabilities	$3.267B	$2.202B	$3.267B
YoY Change	50.22%	9.6%	50.22%
TOTAL LIABILITIES
Total Short-Term Liabilities	$5.342B	$5.136B	$5.342B
Total Long-Term Liabilities	$3.267B	$2.202B	$3.267B
Total Liabilities	$28.46B	$27.88B	$28.46B
YoY Change	-26.46%	-25.93%	-26.47%
SHAREHOLDERS EQUITY
Retained Earnings	$4.041B	$4.219B
YoY Change	13.88%	-31.12%
Common Stock	$1.696B	$1.732B
YoY Change	-13.37%	-62.1%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$122.8M	$122.8M
YoY Change	-54.08%	-97.73%
Treasury Stock Shares	2.296M shares	2.296M shares
Shareholders Equity	$5.464B	$5.744B	$5.464B
YoY Change
Total Liabilities & Shareholders Equity	$33.92B	$33.62B	$33.92B
YoY Change	-24.03%	-22.85%	-24.03%

Cashflow Statement

Concept	2021 Q4	2021 Q3	2021
OPERATING ACTIVITIES
Net Income	$123.6M	$882.4M	$1.372B
YoY Change	-11.21%	-3021.85%	210.64%
Depreciation, Depletion And Amortization	$45.60M	$41.90M	$73.80M
YoY Change	16.33%	4.49%	31.55%
Cash From Operating Activities	$254.7M	-$2.000M	$781.7M
YoY Change	-42.17%	-100.33%	-41.75%
INVESTING ACTIVITIES
Capital Expenditures	-$56.10M	-$46.10M	$187.4M
YoY Change	39.9%	32.09%	54.62%
Acquisitions			$16.60M
YoY Change			-96.38%
Other Investing Activities	$177.0M	$49.50M	-$3.200M
YoY Change	-142.15%	-123.79%	10.34%
Cash From Investing Activities	$120.9M	$3.400M	$157.6M
YoY Change	-126.28%	-101.4%	-121.44%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$839.3M
YoY Change			182.59%
Debt Paid & Issued, Net			$419.8M
YoY Change
Cash From Financing Activities	-332.4M	-736.6M	-$1.090B
YoY Change	-1138.75%	138.54%	311.56%
NET CHANGE
Cash From Operating Activities	254.7M	-2.000M	$781.7M
Cash From Investing Activities	120.9M	3.400M	$157.6M
Cash From Financing Activities	-332.4M	-736.6M	-$1.090B
Net Change In Cash	43.20M	-735.2M	-$173.8M
YoY Change	248.39%	-1376.39%	-148.08%
FREE CASH FLOW
Cash From Operating Activities	$254.7M	-$2.000M	$781.7M
Capital Expenditures	-$56.10M	-$46.10M	$187.4M
Free Cash Flow	$310.8M	$44.10M	$594.3M
YoY Change	-35.32%	-93.16%	-51.32%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2021	dei	Entity Central Index Key EntityCentralIndexKey	0001267238
CY2021	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
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CY2021	dei	Document Type DocumentType	10-K
CY2021	dei	Document Annual Report DocumentAnnualReport	true
CY2021	dei	Document Period End Date DocumentPeriodEndDate	2021-12-31
CY2021	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2021	dei	Document Transition Report DocumentTransitionReport	false
CY2021	dei	Entity File Number EntityFileNumber	001-31978
CY2021	dei	Entity Registrant Name EntityRegistrantName	Assurant, Inc.
CY2021	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2021	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	39-1126612
CY2021	dei	Entity Address Address Line1 EntityAddressAddressLine1	55 Broadway
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CY2021	dei	Entity Address State Or Province EntityAddressStateOrProvince	NY
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CY2020	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
CY2019	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-31400000	USD
CY2021	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	9404600000	USD
CY2020	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	9014700000	USD
CY2019	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	9114400000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	783000000.0	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	580800000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	454700000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	169500000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	60400000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	148300000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	613500000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	520400000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	306400000	USD
CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	758900000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-77700000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	80400000	USD
CY2021	us-gaap	Profit Loss ProfitLoss	1372400000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	442700000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	386800000	USD
CY2021	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
CY2020	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	900000	USD
CY2019	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	4200000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	1372400000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	441800000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	382600000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	382600000	USD
CY2021	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	4700000	USD
CY2020	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	18700000	USD
CY2019	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	18700000	USD
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1367700000	USD
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	1367700000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	423100000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	423100000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	363900000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	363900000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	10.29
CY2020	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	8.33
CY2019	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	4.58
CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	12.84
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	-1.29
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	1.29
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	23.13
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	7.04
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.87
CY2021	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	10.20
CY2020	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	8.22
CY2019	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	4.56
CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	12.63
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	-1.23
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	1.28
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	22.83
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.99
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.84
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	59140861	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	60114670	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	61942969	shares
CY2021	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	982833	shares
CY2020	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	3065268	shares
CY2019	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	370499	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	60123694	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	63179938	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	62313468	shares
CY2021	us-gaap	Profit Loss ProfitLoss	1372400000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	386800000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	442700000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	-233700000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	64000000.0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	153200000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-841000000.0	USD
CY2020	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	225600000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	555900000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-700000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-600000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-400000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-2300000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-2400000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-1300000	USD
CY2021	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	-3100000	USD
CY2020	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	-3800000	USD
CY2019	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	1100000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-31300000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	63300000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	16700000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-3800000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-3200000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	1100000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-14800000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-11800000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	4400000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-859800000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	298300000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	566900000	USD
CY2021	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	512600000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	741000000.0	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	953700000	USD
CY2021	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	0	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	900000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	4200000	USD
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	512600000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	740100000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	949500000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5133900000	USD
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	7100000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	55900000	USD
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.43
CY2019	us-gaap	Dividends Common Stock DividendsCommonStock	151400000	USD
CY2019	us-gaap	Dividends Common Stock DividendsCommonStock	151400000	USD
CY2019	aiz	Decrease To Equity From Acquisition Of Common Stock DecreaseToEquityFromAcquisitionOfCommonStock	295800000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	386800000	USD
CY2019	us-gaap	Preferred Stock Dividends Per Share Declared PreferredStockDividendsPerShareDeclared	6.52
CY2019	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	18700000	USD
CY2019	us-gaap	Minority Interest Period Increase Decrease MinorityInterestPeriodIncreaseDecrease	-2600000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	566900000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5682100000	USD
CY2019	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	18700000	USD
CY2020	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	8600000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	57900000	USD
CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.55
CY2020	us-gaap	Dividends Common Stock DividendsCommonStock	154600000	USD
CY2020	aiz	Decrease To Equity From Acquisition Of Common Stock DecreaseToEquityFromAcquisitionOfCommonStock	320100000	USD
CY2020	us-gaap	Treasury Stock Retired Par Value Method Amount TreasuryStockRetiredParValueMethodAmount	0	USD
CY2020	us-gaap	Profit Loss ProfitLoss	442700000	USD
CY2020	us-gaap	Preferred Stock Dividends Per Share Declared PreferredStockDividendsPerShareDeclared	6.50
CY2020	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	18700000	USD
CY2020	us-gaap	Minority Interest Period Increase Decrease MinorityInterestPeriodIncreaseDecrease	-18700000	USD
CY2020	us-gaap	Minority Interest Decrease From Redemptions MinorityInterestDecreaseFromRedemptions	2300000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	298300000	USD
CY2020Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5954800000	USD
CY2021	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	11800000	USD
CY2021	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	66700000	USD
CY2021	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.66
CY2021	us-gaap	Dividends Common Stock DividendsCommonStock	157600000	USD
CY2021	aiz	Decrease To Equity From Acquisition Of Common Stock DecreaseToEquityFromAcquisitionOfCommonStock	873000000.0	USD
CY2021	us-gaap	Profit Loss ProfitLoss	1372400000	USD
CY2021	us-gaap	Stock Issued During Period Value Conversion Of Convertible Securities StockIssuedDuringPeriodValueConversionOfConvertibleSecurities	0	USD
CY2021	us-gaap	Preferred Stock Dividends Per Share Declared PreferredStockDividendsPerShareDeclared	1.63
CY2021	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	4700000	USD
CY2021	us-gaap	Minority Interest Period Increase Decrease MinorityInterestPeriodIncreaseDecrease	-4000000.0	USD
CY2021	us-gaap	Minority Interest Decrease From Redemptions MinorityInterestDecreaseFromRedemptions	16900000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-859800000	USD
CY2021Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5489700000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	1372400000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	441800000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	382600000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	382600000	USD
CY2021	us-gaap	Other Adjustments To Income Discontinued Operations OtherAdjustmentsToIncomeDiscontinuedOperations	758900000	USD
CY2020	us-gaap	Other Adjustments To Income Discontinued Operations OtherAdjustmentsToIncomeDiscontinuedOperations	-77700000	USD
CY2019	us-gaap	Other Adjustments To Income Discontinued Operations OtherAdjustmentsToIncomeDiscontinuedOperations	80400000	USD
CY2021	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	131700000	USD
CY2020	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	202400000	USD
CY2019	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	100800000	USD
CY2021	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	171600000	USD
CY2020	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	142300000	USD
CY2019	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	125500000	USD
CY2021	us-gaap	Marketable Securities Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesGainLossExcludingOtherThanTemporaryImpairments	128200000	USD
CY2020	us-gaap	Marketable Securities Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesGainLossExcludingOtherThanTemporaryImpairments	-8200000	USD
CY2019	us-gaap	Marketable Securities Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesGainLossExcludingOtherThanTemporaryImpairments	57000000.0	USD
CY2021	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-20700000	USD
CY2020	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
CY2019	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-31400000	USD
CY2021	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	0	USD
CY2020	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	0	USD
CY2019	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	-17000000.0	USD
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	66700000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	57900000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	55900000	USD
CY2021	us-gaap	Impairment Of Intangible Assets Excluding Goodwill ImpairmentOfIntangibleAssetsExcludingGoodwill	1700000	USD
CY2020	us-gaap	Impairment Of Intangible Assets Excluding Goodwill ImpairmentOfIntangibleAssetsExcludingGoodwill	2700000	USD
CY2019	us-gaap	Impairment Of Intangible Assets Excluding Goodwill ImpairmentOfIntangibleAssetsExcludingGoodwill	16200000	USD
CY2021	aiz	Noncash Equity Method Investment Charges Netof Derivative Gains NoncashEquityMethodInvestmentChargesNetofDerivativeGains	0	USD
CY2020	aiz	Noncash Equity Method Investment Charges Netof Derivative Gains NoncashEquityMethodInvestmentChargesNetofDerivativeGains	1700000	USD
CY2019	aiz	Noncash Equity Method Investment Charges Netof Derivative Gains NoncashEquityMethodInvestmentChargesNetofDerivativeGains	163000000.0	USD
CY2021	aiz	Change In Insurance Policy Reserves And Expenses ChangeInInsurancePolicyReservesAndExpenses	1454600000	USD
CY2020	aiz	Change In Insurance Policy Reserves And Expenses ChangeInInsurancePolicyReservesAndExpenses	697300000	USD
CY2019	aiz	Change In Insurance Policy Reserves And Expenses ChangeInInsurancePolicyReservesAndExpenses	1304500000	USD
CY2021	aiz	Change In Premiums And Accounts Receivable ChangeInPremiumsAndAccountsReceivable	424200000	USD
CY2020	aiz	Change In Premiums And Accounts Receivable ChangeInPremiumsAndAccountsReceivable	-194000000.0	USD
CY2019	aiz	Change In Premiums And Accounts Receivable ChangeInPremiumsAndAccountsReceivable	58500000	USD
CY2021	aiz	Increase Decreasein Commissions Payable IncreaseDecreaseinCommissionsPayable	-43300000	USD
CY2020	aiz	Increase Decreasein Commissions Payable IncreaseDecreaseinCommissionsPayable	171300000	USD
CY2019	aiz	Increase Decreasein Commissions Payable IncreaseDecreaseinCommissionsPayable	102600000	USD
CY2021	us-gaap	Increase Decrease In Reinsurance Recoverable IncreaseDecreaseInReinsuranceRecoverable	445500000	USD
CY2020	us-gaap	Increase Decrease In Reinsurance Recoverable IncreaseDecreaseInReinsuranceRecoverable	232300000	USD
CY2019	us-gaap	Increase Decrease In Reinsurance Recoverable IncreaseDecreaseInReinsuranceRecoverable	404300000	USD
CY2021	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	81600000	USD
CY2020	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	2300000	USD
CY2019	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	25700000	USD
CY2021	us-gaap	Increase Decrease In Funds Held Under Reinsurance Agreements IncreaseDecreaseInFundsHeldUnderReinsuranceAgreements	-6500000	USD
CY2020	us-gaap	Increase Decrease In Funds Held Under Reinsurance Agreements IncreaseDecreaseInFundsHeldUnderReinsuranceAgreements	-37900000	USD
CY2019	us-gaap	Increase Decrease In Funds Held Under Reinsurance Agreements IncreaseDecreaseInFundsHeldUnderReinsuranceAgreements	-44600000	USD
CY2021	aiz	Change In Deferred Acquisition Costs And Value Of Business Acquired ChangeInDeferredAcquisitionCostsAndValueOfBusinessAcquired	879100000	USD
CY2020	aiz	Change In Deferred Acquisition Costs And Value Of Business Acquired ChangeInDeferredAcquisitionCostsAndValueOfBusinessAcquired	456600000	USD
CY2019	aiz	Change In Deferred Acquisition Costs And Value Of Business Acquired ChangeInDeferredAcquisitionCostsAndValueOfBusinessAcquired	780700000	USD
CY2021	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	-157100000	USD
CY2020	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	24400000	USD
CY2019	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	14100000	USD
CY2021	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-163200000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	260900000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-105000000.0	USD
CY2021	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	3900000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-2200000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-20300000	USD
CY2021	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	151200000	USD
CY2020	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	227700000	USD
CY2019	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	285100000	USD
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	781700000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	1342000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	1413400000	USD
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	1361800000	USD
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	515400000	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	1729800000	USD
CY2021	aiz	Proceeds From The Sale Of Equity Securities ProceedsFromTheSaleOfEquitySecurities	30400000	USD
CY2020	aiz	Proceeds From The Sale Of Equity Securities ProceedsFromTheSaleOfEquitySecurities	23800000	USD
CY2019	aiz	Proceeds From The Sale Of Equity Securities ProceedsFromTheSaleOfEquitySecurities	77400000	USD
CY2021	us-gaap	Proceeds From Sale Of Other Investments ProceedsFromSaleOfOtherInvestments	141100000	USD
CY2020	us-gaap	Proceeds From Sale Of Other Investments ProceedsFromSaleOfOtherInvestments	113100000	USD
CY2019	us-gaap	Proceeds From Sale Of Other Investments ProceedsFromSaleOfOtherInvestments	128900000	USD
CY2021	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	1315600000	USD
CY2020	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	0	USD
CY2019	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	0	USD
CY2021	us-gaap	Proceeds From Hedge Investing Activities ProceedsFromHedgeInvestingActivities	0	USD
CY2020	us-gaap	Proceeds From Hedge Investing Activities ProceedsFromHedgeInvestingActivities	22000000.0	USD
CY2019	us-gaap	Proceeds From Hedge Investing Activities ProceedsFromHedgeInvestingActivities	0	USD
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	971000000.0	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	804800000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	541200000	USD
CY2021	us-gaap	Proceeds From Sale And Collection Of Mortgage Notes Receivable ProceedsFromSaleAndCollectionOfMortgageNotesReceivable	19800000	USD
CY2020	us-gaap	Proceeds From Sale And Collection Of Mortgage Notes Receivable ProceedsFromSaleAndCollectionOfMortgageNotesReceivable	26200000	USD
CY2019	us-gaap	Proceeds From Sale And Collection Of Mortgage Notes Receivable ProceedsFromSaleAndCollectionOfMortgageNotesReceivable	18100000	USD
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	3007700000	USD
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1503900000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	2183000000	USD
CY2021	aiz	Payments To Acquire Equity Securities PaymentsToAcquireEquitySecurities	57700000	USD
CY2020	aiz	Payments To Acquire Equity Securities PaymentsToAcquireEquitySecurities	31500000	USD
CY2019	aiz	Payments To Acquire Equity Securities PaymentsToAcquireEquitySecurities	73200000	USD
CY2021	us-gaap	Payments To Acquire Mortgage Notes Receivable PaymentsToAcquireMortgageNotesReceivable	133900000	USD
CY2020	us-gaap	Payments To Acquire Mortgage Notes Receivable PaymentsToAcquireMortgageNotesReceivable	5500000	USD
CY2019	us-gaap	Payments To Acquire Mortgage Notes Receivable PaymentsToAcquireMortgageNotesReceivable	0	USD
CY2021	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	71600000	USD
CY2020	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	99500000	USD
CY2019	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	50800000	USD
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	187400000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	121200000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	110300000	USD
CY2021	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	16600000	USD
CY2020	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	458600000	USD
CY2019	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	7600000	USD
CY2021	aiz	Equity Method Investment Payment On Divestment EquityMethodInvestmentPaymentOnDivestment	0	USD
CY2020	aiz	Equity Method Investment Payment On Divestment EquityMethodInvestmentPaymentOnDivestment	73300000	USD
CY2019	aiz	Equity Method Investment Payment On Divestment EquityMethodInvestmentPaymentOnDivestment	0	USD
CY2021	aiz	Purchasesof Investmentsby Special Purpose Entities PurchasesofInvestmentsbySpecialPurposeEntities	0	USD
CY2020	aiz	Purchasesof Investmentsby Special Purpose Entities PurchasesofInvestmentsbySpecialPurposeEntities	353100000	USD
CY2019	aiz	Purchasesof Investmentsby Special Purpose Entities PurchasesofInvestmentsbySpecialPurposeEntities	1311000000	USD
CY2021	aiz	Proceedsfrom Salesand Redemptionsof Investmentsby Special Purpose Entities ProceedsfromSalesandRedemptionsofInvestmentsbySpecialPurposeEntities	0	USD
CY2020	aiz	Proceedsfrom Salesand Redemptionsof Investmentsby Special Purpose Entities ProceedsfromSalesandRedemptionsofInvestmentsbySpecialPurposeEntities	550200000	USD
CY2019	aiz	Proceedsfrom Salesand Redemptionsof Investmentsby Special Purpose Entities ProceedsfromSalesandRedemptionsofInvestmentsbySpecialPurposeEntities	935100000	USD
CY2021	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	65200000	USD
CY2020	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	-68800000	USD
CY2019	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	39000000.0	USD
CY2021	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-3200000	USD
CY2020	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-2900000	USD
CY2019	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-7500000	USD
CY2021	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-145200000	USD
CY2020	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-215800000	USD
CY2019	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-282900000	USD
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	157600000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-735200000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-619800000	USD
CY2021	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	347200000	USD
CY2020	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	243700000	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	346700000	USD
CY2021	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	419800000	USD
CY2020	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	379600000	USD
CY2021	aiz	Proceedsfrom Issuanceof Collateralized Loan Obligations ProceedsfromIssuanceofCollateralizedLoanObligations	0	USD
CY2020	aiz	Proceedsfrom Issuanceof Collateralized Loan Obligations ProceedsfromIssuanceofCollateralizedLoanObligations	0	USD
CY2019	aiz	Proceedsfrom Issuanceof Collateralized Loan Obligations ProceedsfromIssuanceofCollateralizedLoanObligations	398600000	USD
CY2021	aiz	Special Purpose Entity Proceeds From Issuance Of Long Term Debt SpecialPurposeEntityProceedsFromIssuanceOfLongTermDebt	0	USD
CY2020	aiz	Special Purpose Entity Proceeds From Issuance Of Long Term Debt SpecialPurposeEntityProceedsFromIssuanceOfLongTermDebt	0	USD
CY2019	aiz	Special Purpose Entity Proceeds From Issuance Of Long Term Debt SpecialPurposeEntityProceedsFromIssuanceOfLongTermDebt	189100000	USD
CY2021	aiz	Special Purpose Entity Repaymentsof Debt SpecialPurposeEntityRepaymentsofDebt	0	USD
CY2020	aiz	Special Purpose Entity Repaymentsof Debt SpecialPurposeEntityRepaymentsofDebt	1200000	USD
CY2019	aiz	Special Purpose Entity Repaymentsof Debt SpecialPurposeEntityRepaymentsofDebt	319300000	USD
CY2021	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	0	USD
CY2020	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	200000000.0	USD
CY2019	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	0	USD
CY2021	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	0	USD
CY2020	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	200000000.0	USD
CY2019	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	0	USD
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	839300000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	297000000.0	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	271800000	USD
CY2021	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	157600000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	154600000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	151400000	USD
CY2021	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	4700000	USD
CY2020	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	18700000	USD
CY2019	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	18700000	USD
CY2021	aiz	Payments Related To Tax Withholding For Share Based Compensation Net Of Proceeds From Employee PaymentsRelatedToTaxWithholdingForShareBasedCompensationNetOfProceedsFromEmployee	15600000	USD
CY2020	aiz	Payments Related To Tax Withholding For Share Based Compensation Net Of Proceeds From Employee PaymentsRelatedToTaxWithholdingForShareBasedCompensationNetOfProceedsFromEmployee	10300000	USD
CY2019	aiz	Payments Related To Tax Withholding For Share Based Compensation Net Of Proceeds From Employee PaymentsRelatedToTaxWithholdingForShareBasedCompensationNetOfProceedsFromEmployee	-19700000	USD
CY2021	aiz	Participation Rights Agreement Upfront Payment Received ParticipationRightsAgreementUpfrontPaymentReceived	0	USD
CY2020	aiz	Participation Rights Agreement Upfront Payment Received ParticipationRightsAgreementUpfrontPaymentReceived	0	USD
CY2019	aiz	Participation Rights Agreement Upfront Payment Received ParticipationRightsAgreementUpfrontPaymentReceived	26700000	USD
CY2021	aiz	Repayment Of Upfront Payment Of Participation Rights Agreement RepaymentOfUpfrontPaymentOfParticipationRightsAgreement	0	USD
CY2020	aiz	Repayment Of Upfront Payment Of Participation Rights Agreement RepaymentOfUpfrontPaymentOfParticipationRightsAgreement	26700000	USD
CY2019	aiz	Repayment Of Upfront Payment Of Participation Rights Agreement RepaymentOfUpfrontPaymentOfParticipationRightsAgreement	0	USD
CY2021	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	0	USD
CY2020	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	0	USD
CY2019	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-19200000	USD
CY2021	us-gaap	Cash Provided By Used In Financing Activities Discontinued Operations CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations	0	USD
CY2020	us-gaap	Cash Provided By Used In Financing Activities Discontinued Operations CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations	0	USD
CY2019	us-gaap	Cash Provided By Used In Financing Activities Discontinued Operations CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations	0	USD
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-1089800000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-264800000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-179200000	USD
CY2021	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-23500000	USD
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	19400000	USD
CY2019	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-1600000	USD
CY2021	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Disposal Group Including Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations	200000	USD
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Disposal Group Including Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations	100000	USD
CY2019	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Disposal Group Including Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations	300000	USD
CY2021	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	-23300000	USD
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	19500000	USD
CY2019	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	-1300000	USD
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-173800000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	361500000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	613100000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	2228600000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	1867100000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	1254000000	USD
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	2054800000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	2228600000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	1867100000	USD
CY2021Q4	aiz	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Disposal Group Held For Sale Not Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupHeldForSaleNotDiscontinuedOperations	14000000.0	USD
CY2020Q4	aiz	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Disposal Group Held For Sale Not Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupHeldForSaleNotDiscontinuedOperations	0	USD
CY2019Q4	aiz	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Disposal Group Held For Sale Not Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupHeldForSaleNotDiscontinuedOperations	0	USD
CY2021Q4	aiz	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Disposal Group Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupDiscontinuedOperations	0	USD
CY2020Q4	aiz	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Disposal Group Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupDiscontinuedOperations	21000000.0	USD
CY2019Q4	aiz	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Disposal Group Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupDiscontinuedOperations	9000000.0	USD
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	2040800000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	2207600000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	1858100000	USD
CY2021	us-gaap	Income Taxes Paid IncomeTaxesPaid	221100000	USD
CY2020	us-gaap	Income Taxes Paid IncomeTaxesPaid	98500000	USD
CY2019	us-gaap	Income Taxes Paid IncomeTaxesPaid	93100000	USD
CY2021	us-gaap	Interest Paid Net InterestPaidNet	109800000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	103600000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	103200000	USD
CY2020	aiz	Proceeds From Income Tax Refunds Cares Act ProceedsFromIncomeTaxRefundsCARESAct	204900000	USD
CY2021	us-gaap	Nature Of Operations NatureOfOperations	Nature of Operations Assurant, Inc. (the “Company”) is a global provider of lifestyle and housing solutions that support, protect and connect major consumer purchases. The Company partners with leading brands to develop innovative products and services and to deliver enhanced customer experience. The Company operates in North America, Latin America, Europe and Asia Pacific through two operating segments: Global Lifestyle and Global Housing. Through its Global Lifestyle segment, the Company provides mobile device solutions and extended service products and related services for consumer electronics and appliances (referred to as “Connected Living”); vehicle protection and related services (referred to as “Global Automotive”); and credit protection and other insurance products (referred to as “Global Financial Services and Other”). Through its Global Housing segment, the Company provides lender-placed homeowners insurance, lender-placed manufactured housing insurance and lender-placed flood insurance (referred to as “Lender-placed Insurance”); renters insurance and related products (referred to as “Multifamily Housing”); and voluntary manufactured housing insurance, voluntary homeowners insurance and other specialty products (referred to as “Specialty and Other”). The businesses previously reported as the Global Preneed segment, through which the Company provided pre-funded funeral insurance, final need insurance and related services, as well as certain businesses previously disposed of through reinsurance, were sold in August 2021. Refer to Note 4 for additional information on the sale.The Company’s common stock is traded on the New York Stock Exchange under the symbol “AIZ.”
CY2021	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	2	segment
CY2021	us-gaap	Use Of Estimates UseOfEstimates	<div style="margin-bottom:6pt;text-indent:22.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates</span></div><div style="margin-bottom:6pt;text-indent:22.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts. The items affected by the use of estimates include but are not limited to, investments, reinsurance recoverables, premium and accounts receivables, deferred acquisition costs (“DAC”), value of business acquired (“VOBA”), deferred income taxes and associated valuation allowances, goodwill, intangible assets, future policy benefits and expenses, unearned premiums, claims and benefits payable, deferred gain on disposal of businesses, pension and post-retirement liabilities and commitments and contingencies. The estimates are sensitive to market conditions, investment yields, mortality, morbidity, commissions and other acquisition expenses, policyholder behavior and other factors. Actual results could differ from the estimates recorded. The Company believes all amounts reported are reasonable and adequate.</span></div>
CY2021	aiz	Loss From Remeasurement Due To Highly Inflationary Accounting LossFromRemeasurementDueToHighlyInflationaryAccounting	7000000	USD
CY2020	aiz	Loss From Remeasurement Due To Highly Inflationary Accounting LossFromRemeasurementDueToHighlyInflationaryAccounting	7500000	USD
CY2019	aiz	Loss From Remeasurement Due To Highly Inflationary Accounting LossFromRemeasurementDueToHighlyInflationaryAccounting	18400000	USD
CY2021	aiz	Loans Receivable Nonaccrual Loan Number Of Days Delinquent LoansReceivableNonaccrualLoanNumberOfDaysDelinquent	P90D
CY2021Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	27900000	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	14600000	USD
CY2021Q4	us-gaap	Liability For Future Policy Benefits LiabilityForFuturePolicyBenefits	413200000	USD
CY2021Q4	us-gaap	Unearned Premiums UnearnedPremiums	18623700000	USD
CY2021Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Reported Claims Amount LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseReportedClaimsAmount	579200000	USD
CY2021Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred But Not Reported Ibnr Claims Amount LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredButNotReportedIBNRClaimsAmount	1016700000	USD
CY2020Q4	us-gaap	Liability For Future Policy Benefits LiabilityForFuturePolicyBenefits	1358500000	USD
CY2020Q4	us-gaap	Unearned Premiums UnearnedPremiums	17293100000	USD
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Reported Claims Amount LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseReportedClaimsAmount	610400000	USD
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred But Not Reported Ibnr Claims Amount LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredButNotReportedIBNRClaimsAmount	999900000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	80400000	USD
CY2016Q4	aiz	Aca Risk Corridor Programs Receivables Valuation Allowance ACARiskCorridorProgramsReceivablesValuationAllowance	106700000	USD
CY2021Q4	aiz	Receivable Allowancefor Credit Loss ReceivableAllowanceforCreditLoss	18000000	USD
CY2020Q4	aiz	Receivable Allowancefor Credit Loss ReceivableAllowanceforCreditLoss	43900000	USD
CY2021	aiz	Receivable Allowancefor Credit Losses Period Increase Decrease Net ReceivableAllowanceforCreditLossesPeriodIncreaseDecreaseNet	-3500000	USD
CY2020	aiz	Receivable Allowancefor Credit Losses Period Increase Decrease Net ReceivableAllowanceforCreditLossesPeriodIncreaseDecreaseNet	7400000	USD
CY2021Q4	us-gaap	Reinsurance Recoverables ReinsuranceRecoverables	6180000000	USD
CY2020Q4	us-gaap	Reinsurance Recoverables ReinsuranceRecoverables	6610000000	USD
CY2019Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	2800000	USD
CY2020	us-gaap	Reinsurance Recoverable Credit Loss Expense Reversal ReinsuranceRecoverableCreditLossExpenseReversal	3300000	USD
CY2020	us-gaap	Reinsurance Recoverable Allowance For Credit Loss Recovery ReinsuranceRecoverableAllowanceForCreditLossRecovery	2500000	USD
CY2020	aiz	Reinsurance Recoverable Allowance For Cred Loss Period Increase Decrease Other ReinsuranceRecoverableAllowanceForCredLossPeriodIncreaseDecreaseOther	300000	USD
CY2020Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	24600000	USD
CY2021	us-gaap	Reinsurance Recoverable Credit Loss Expense Reversal ReinsuranceRecoverableCreditLossExpenseReversal	-1500000	USD
CY2021	aiz	Reinsurance Recoverable Allowance For Cred Loss Period Increase Decrease Other ReinsuranceRecoverableAllowanceForCredLossPeriodIncreaseDecreaseOther	-18100000	USD
CY2021Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	5000000.0	USD
CY2021	us-gaap	Reinsurance Recoverable Credit Loss Expense Reversal ReinsuranceRecoverableCreditLossExpenseReversal	-1500000	USD
CY2020	us-gaap	Reinsurance Recoverable Credit Loss Expense Reversal ReinsuranceRecoverableCreditLossExpenseReversal	3300000	USD
CY2019Q4	aiz	Premiums And Accounts Receivable Allowance For Credit Loss PremiumsAndAccountsReceivableAllowanceForCreditLoss	14800000	USD
CY2020	aiz	Premiums And Accounts Receivable Allowance For Credit Loss Period Increase Decrease PremiumsAndAccountsReceivableAllowanceForCreditLossPeriodIncreaseDecrease	4000000.0	USD
CY2020	aiz	Premiums And Accounts Receivable Allowance For Credit Loss Recovery PremiumsAndAccountsReceivableAllowanceForCreditLossRecovery	1400000	USD
CY2020	aiz	Premiums And Accounts Receivable Allowance For Credit Loss Writeoff PremiumsAndAccountsReceivableAllowanceForCreditLossWriteoff	5600000	USD
CY2020	aiz	Premiumsand Accounts Receivable Allowance For Credit Loss Foreign Currency Translationand Other PremiumsandAccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationandOther	300000	USD
CY2020Q4	aiz	Premiums And Accounts Receivable Allowance For Credit Loss PremiumsAndAccountsReceivableAllowanceForCreditLoss	13300000	USD
CY2021	aiz	Premiums And Accounts Receivable Allowance For Credit Loss Period Increase Decrease PremiumsAndAccountsReceivableAllowanceForCreditLossPeriodIncreaseDecrease	-700000	USD
CY2021	aiz	Premiums And Accounts Receivable Allowance For Credit Loss Recovery PremiumsAndAccountsReceivableAllowanceForCreditLossRecovery	700000	USD
CY2021	aiz	Premiums And Accounts Receivable Allowance For Credit Loss Writeoff PremiumsAndAccountsReceivableAllowanceForCreditLossWriteoff	2200000	USD
CY2021	aiz	Premiumsand Accounts Receivable Allowance For Credit Loss Foreign Currency Translationand Other PremiumsandAccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationandOther	300000	USD
CY2021Q4	aiz	Premiums And Accounts Receivable Allowance For Credit Loss PremiumsAndAccountsReceivableAllowanceForCreditLoss	9400000	USD
CY2021	aiz	Premiums And Accounts Receivable Allowance For Credit Loss Period Increase Decrease PremiumsAndAccountsReceivableAllowanceForCreditLossPeriodIncreaseDecrease	-700000	USD
CY2020	aiz	Premiums And Accounts Receivable Allowance For Credit Loss Period Increase Decrease PremiumsAndAccountsReceivableAllowanceForCreditLossPeriodIncreaseDecrease	4000000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	300000	USD
CY2020Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	400000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	1200000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0	USD
CY2021	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	segment
CY2021	us-gaap	Premiums Earned Net PremiumsEarnedNet	8572100000	USD
CY2021	us-gaap	Other Income OtherIncome	1172900000	USD
CY2021	us-gaap	Net Investment Income NetInvestmentIncome	314400000	USD
CY2021	us-gaap	Gain Loss On Investments GainLossOnInvestments	128200000	USD
CY2021	us-gaap	Revenues Revenues	10187600000	USD
CY2021	us-gaap	Policyholder Benefits And Claims Incurred Net PolicyholderBenefitsAndClaimsIncurredNet	2195700000	USD
CY2021	aiz	Amortization Of Deferred Acquisition Costs And Value Of Business Acquired AmortizationOfDeferredAcquisitionCostsAndValueOfBusinessAcquired	3835800000	USD
CY2021	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	3240600000	USD
CY2021	us-gaap	Interest Expense InterestExpense	111800000	USD
CY2021	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-20700000	USD
CY2021	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	9404600000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	783000000.0	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	169500000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	613500000	USD
CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	758900000	USD
CY2021	us-gaap	Profit Loss ProfitLoss	1372400000	USD
CY2021	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	1372400000	USD
CY2021	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	4700000	USD
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1367700000	USD
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	1367700000	USD
CY2021Q4	us-gaap	Assets Assets	33911500000	USD
CY2020	us-gaap	Premiums Earned Net PremiumsEarnedNet	8275800000	USD
CY2020	us-gaap	Other Income OtherIncome	1042300000	USD
CY2020	us-gaap	Net Investment Income NetInvestmentIncome	285600000	USD
CY2020	us-gaap	Gain Loss On Investments GainLossOnInvestments	-8200000	USD
CY2020	us-gaap	Revenues Revenues	9595500000	USD
CY2020	us-gaap	Policyholder Benefits And Claims Incurred Net PolicyholderBenefitsAndClaimsIncurredNet	2264900000	USD
CY2020	aiz	Amortization Of Deferred Acquisition Costs And Value Of Business Acquired AmortizationOfDeferredAcquisitionCostsAndValueOfBusinessAcquired	3591500000	USD
CY2020	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	3047900000	USD
CY2020	aiz	Investment Related Charges Netof Derivative Gains InvestmentRelatedChargesNetofDerivativeGains	5900000	USD
CY2020	us-gaap	Interest Expense InterestExpense	104500000	USD
CY2020	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	9014700000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	580800000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	60400000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	520400000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-77700000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	442700000	USD
CY2020	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	900000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	441800000	USD
CY2020	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	18700000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	423100000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	423100000	USD
CY2020Q4	us-gaap	Assets Assets	44649900000	USD
CY2019	us-gaap	Premiums Earned Net PremiumsEarnedNet	7958800000	USD
CY2019	us-gaap	Other Income OtherIncome	1170100000	USD
CY2019	us-gaap	Net Investment Income NetInvestmentIncome	383200000	USD
CY2019	us-gaap	Gain Loss On Investments GainLossOnInvestments	57000000.0	USD
CY2019	us-gaap	Revenues Revenues	9569100000	USD
CY2019	us-gaap	Policyholder Benefits And Claims Incurred Net PolicyholderBenefitsAndClaimsIncurredNet	2385700000	USD
CY2019	aiz	Amortization Of Deferred Acquisition Costs And Value Of Business Acquired AmortizationOfDeferredAcquisitionCostsAndValueOfBusinessAcquired	3237200000	USD
CY2019	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	3186500000	USD
CY2019	aiz	Investment Related Charges Netof Derivative Gains InvestmentRelatedChargesNetofDerivativeGains	163000000.0	USD
CY2019	us-gaap	Interest Expense InterestExpense	110600000	USD
CY2019	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-31400000	USD
CY2019	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	9114400000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	454700000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	148300000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	306400000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	80400000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	386800000	USD
CY2019	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	4200000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	382600000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	382600000	USD
CY2019	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	18700000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	363900000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	363900000	USD
CY2021	us-gaap	Revenues Revenues	10187600000	USD
CY2021Q4	us-gaap	Noncurrent Assets NoncurrentAssets	561400000	USD
CY2020	us-gaap	Revenues Revenues	9595500000	USD
CY2020Q4	us-gaap	Noncurrent Assets NoncurrentAssets	446100000	USD
CY2019	us-gaap	Revenues Revenues	9569100000	USD
CY2019Q4	us-gaap	Noncurrent Assets NoncurrentAssets	390700000	USD
CY2021Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	313700000	USD
CY2021Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	191500000	USD
CY2020Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	257900000	USD
CY2020Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	89800000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	376900000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	381100000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	2117300000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	2200700000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	1892800000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	1988500000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	1060700000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	1146400000	USD
CY2021Q4	aiz	Available For Sale Securities Debt Maturities Contractual Maturity Total AvailableForSaleSecuritiesDebtMaturitiesContractualMaturityTotal	5447700000	USD
CY2021Q4	aiz	Available For Sale Securities Debt Maturities Contractual Maturity Fair Value Total AvailableForSaleSecuritiesDebtMaturitiesContractualMaturityFairValueTotal	5716700000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	6903900000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	7215300000	USD
CY2021	us-gaap	Gross Investment Income Operating GrossInvestmentIncomeOperating	328200000	USD
CY2020	us-gaap	Gross Investment Income Operating GrossInvestmentIncomeOperating	343000000.0	USD
CY2019	us-gaap	Gross Investment Income Operating GrossInvestmentIncomeOperating	473600000	USD
CY2021	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	13800000	USD
CY2020	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	20500000	USD
CY2019	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	20300000	USD
CY2021	us-gaap	Net Investment Income NetInvestmentIncome	314400000	USD
CY2020	us-gaap	Net Investment Income NetInvestmentIncome	285600000	USD
CY2019	us-gaap	Net Investment Income NetInvestmentIncome	383200000	USD
CY2019	aiz	Non Income Producing Material Investments NonIncomeProducingMaterialInvestments	0	USD
CY2021	aiz	Non Income Producing Material Investments NonIncomeProducingMaterialInvestments	0	USD
CY2020	aiz	Non Income Producing Material Investments NonIncomeProducingMaterialInvestments	0	USD
CY2021	aiz	Proceedsfrom Saleof Debt Securities Availableforsale Including Proceedsin Transit ProceedsfromSaleofDebtSecuritiesAvailableforsaleIncludingProceedsinTransit	1361800000	USD
CY2020	aiz	Proceedsfrom Saleof Debt Securities Availableforsale Including Proceedsin Transit ProceedsfromSaleofDebtSecuritiesAvailableforsaleIncludingProceedsinTransit	515400000	USD
CY2019	aiz	Proceedsfrom Saleof Debt Securities Availableforsale Including Proceedsin Transit ProceedsfromSaleofDebtSecuritiesAvailableforsaleIncludingProceedsinTransit	1729100000	USD
CY2021	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	31900000	USD
CY2020	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	19600000	USD
CY2019	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	24300000	USD
CY2021	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	14800000	USD
CY2020	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	6800000	USD
CY2019	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	8200000	USD
CY2021	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	17100000	USD
CY2020	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	12800000	USD
CY2019	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	16100000	USD
CY2021	aiz	Average Period Of Time These Securities Traded Continuously At Price Below Book Value AveragePeriodOfTimeTheseSecuritiesTradedContinuouslyAtPriceBelowBookValue	P6M
CY2021	aiz	Realized Investment Gains Loss Relatedto Salesand Other RealizedInvestmentGainsLossRelatedtoSalesandOther	128000000.0	USD
CY2020	aiz	Realized Investment Gains Loss Relatedto Salesand Other RealizedInvestmentGainsLossRelatedtoSalesandOther	11500000	USD
CY2019	aiz	Realized Investment Gains Loss Relatedto Salesand Other RealizedInvestmentGainsLossRelatedtoSalesandOther	59100000	USD
CY2021	aiz	Investment Impairment Lossesincludedin Net Realized Gains Losses InvestmentImpairmentLossesincludedinNetRealizedGainsLosses	-200000	USD
CY2020	aiz	Investment Impairment Lossesincludedin Net Realized Gains Losses InvestmentImpairmentLossesincludedinNetRealizedGainsLosses	19700000	USD
CY2019	aiz	Investment Impairment Lossesincludedin Net Realized Gains Losses InvestmentImpairmentLossesincludedinNetRealizedGainsLosses	2100000	USD
CY2021	us-gaap	Gain Loss On Investments GainLossOnInvestments	128200000	USD
CY2020	us-gaap	Gain Loss On Investments GainLossOnInvestments	-8200000	USD
CY2019	us-gaap	Gain Loss On Investments GainLossOnInvestments	57000000.0	USD
CY2021	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	24300000	USD
CY2020	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	10500000	USD
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	13400000	USD
CY2021	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	1000000	USD
CY2020	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	17100000	USD
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	1500000	USD
CY2021Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount	43000000	USD
CY2020Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount	35100000	USD
CY2019Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount	24600000	USD
CY2021Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount	800000	USD
CY2020Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount	0	USD
CY2019Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount	0	USD
CY2021Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount	14900000	USD
CY2020Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount	18600000	USD
CY2019Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount	1500000	USD
CY2021	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	108300000	USD
CY2020	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	21600000	USD
CY2019	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	37400000	USD
CY2021	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	4100000	USD
CY2020	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	-6600000	USD
CY2019	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	1100000	USD
CY2021	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	112400000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	15000000.0	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	38500000	USD
CY2021Q4	aiz	Available For Sale Securities Gross Unrealized Losses Percentage AvailableForSaleSecuritiesGrossUnrealizedLossesPercentage	0.02
CY2020Q4	aiz	Available For Sale Securities Gross Unrealized Losses Percentage AvailableForSaleSecuritiesGrossUnrealizedLossesPercentage	0.02
CY2021Q4	aiz	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses Percentage AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesPercentage	0.94
CY2020Q4	aiz	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses Percentage AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesPercentage	0.60
CY2021Q4	aiz	Number Of Available For Sale Securities Comprising Gross Unrealized Loss NumberOfAvailableForSaleSecuritiesComprisingGrossUnrealizedLoss	1202	security
CY2020Q4	aiz	Number Of Available For Sale Securities Comprising Gross Unrealized Loss NumberOfAvailableForSaleSecuritiesComprisingGrossUnrealizedLoss	180	security
CY2021Q4	aiz	Due In One Year Or Less Cost Or Amortized Cost Net Of Allowance DueInOneYearOrLessCostOrAmortizedCostNetOfAllowance	15300000	USD
CY2021Q4	aiz	Available For Sale Securities Debt Maturities In Unrealized Loss Position Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesInUnrealizedLossPositionWithinOneYearFairValue	15100000	USD
CY2021Q4	aiz	Due After One Year Through Five Years Cost Or Amortized Cost Net Of Allowance DueAfterOneYearThroughFiveYearsCostOrAmortizedCostNetOfAllowance	443200000	USD
CY2021Q4	aiz	Available For Sale Securities Debt Maturities In Unrealized Loss Position After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesInUnrealizedLossPositionAfterOneThroughFiveYearsFairValue	436600000	USD
CY2021Q4	aiz	Due After Five Year Through Ten Years Cost Or Amortized Cost Net Of Allowance DueAfterFiveYearThroughTenYearsCostOrAmortizedCostNetOfAllowance	602900000	USD
CY2021Q4	aiz	Available For Sale Securities Debt Maturities In Unrealized Loss Position After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesInUnrealizedLossPositionAfterFiveThroughTenYearsFairValue	591300000	USD
CY2021Q4	aiz	Due After Ten Years Cost Or Amortized Cost Net Of Allowance DueAfterTenYearsCostOrAmortizedCostNetOfAllowance	369800000	USD
CY2021Q4	aiz	Available For Sale Securities Debt Maturities In Unrealized Loss Position After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesInUnrealizedLossPositionAfterTenYearsFairValue	360300000	USD
CY2021Q4	us-gaap	Premiums And Other Receivables Net PremiumsAndOtherReceivablesNet	1942500000	USD
CY2020Q4	us-gaap	Premiums And Other Receivables Net PremiumsAndOtherReceivablesNet	1548900000	USD
CY2021Q4	aiz	Total Single Maturity Date Cost Or Amortized Cost Net Of Allowance TotalSingleMaturityDateCostOrAmortizedCostNetOfAllowance	1431200000	USD
CY2021Q4	aiz	Available For Sale Securities Debt Maturities In Unrealized Loss Position Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesInUnrealizedLossPositionSingleMaturityDate	1403300000	USD
CY2021Q4	aiz	Total Cost Or Amortized Cost Net Of Allowance TotalCostOrAmortizedCostNetOfAllowance	2086800000	USD
CY2021Q4	aiz	Available For Sale Securities Debt Securities In Unrealized Loss Position AvailableForSaleSecuritiesDebtSecuritiesInUnrealizedLossPosition	2051600000	USD
CY2021	aiz	Approximate Percentage Outstanding Principal Balance Of Commercial Mortgage Loans ApproximatePercentageOutstandingPrincipalBalanceOfCommercialMortgageLoans	0.38
CY2021Q4	aiz	Mortgage Loans Unfunded Commitment MortgageLoansUnfundedCommitment	14100000	USD
CY2021Q4	aiz	Short Term Investments And Fixed Maturities ShortTermInvestmentsAndFixedMaturities	537400000	USD
CY2020Q4	aiz	Short Term Investments And Fixed Maturities ShortTermInvestmentsAndFixedMaturities	587300000	USD
CY2021Q4	us-gaap	Variable Interest Entity Entity Maximum Loss Exposure Amount VariableInterestEntityEntityMaximumLossExposureAmount	249300000	USD
CY2020Q4	us-gaap	Variable Interest Entity Entity Maximum Loss Exposure Amount VariableInterestEntityEntityMaximumLossExposureAmount	253900000	USD
CY2021Q4	aiz	Variable Interest Entity Unfunded Commitments VariableInterestEntityUnfundedCommitments	38800000	USD
CY2021	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	1000000	USD
CY2020	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	17100000	USD
CY2021	us-gaap	Premiums Receivable Note PremiumsReceivableNote	Premiums and Accounts Receivable Receivables are reported net of an allowance for uncollectible amounts. A summary of such receivables is as follows as of the dates indicated:<table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:99.853%"><tr><td style="width:1.0%"/><td style="width:72.692%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.637%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.532%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.639%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">December 31,</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2021</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Insurance premiums receivable</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,878.0 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,484.2 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Other receivables</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">73.9 </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">78.0 </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Allowance for credit losses</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(9.4)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(13.3)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 19pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,942.5 </span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,548.9 </span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table>
CY2021Q4	us-gaap	Premiums Receivable At Carrying Value PremiumsReceivableAtCarryingValue	1878000000	USD
CY2020Q4	us-gaap	Premiums Receivable At Carrying Value PremiumsReceivableAtCarryingValue	1484200000	USD
CY2021Q4	us-gaap	Other Receivables OtherReceivables	73900000	USD
CY2020Q4	us-gaap	Other Receivables OtherReceivables	78000000.0	USD
CY2021Q4	aiz	Premiums And Accounts Receivable Allowance For Credit Loss PremiumsAndAccountsReceivableAllowanceForCreditLoss	9400000	USD
CY2020Q4	aiz	Premiums And Accounts Receivable Allowance For Credit Loss PremiumsAndAccountsReceivableAllowanceForCreditLoss	13300000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	629700000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	443100000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	414700000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	153300000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	137700000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	40000000.0	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	783000000.0	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	580800000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	454700000	USD
CY2021	us-gaap	Current Federal State And Local Tax Expense Benefit CurrentFederalStateAndLocalTaxExpenseBenefit	1700000	USD
CY2020	us-gaap	Current Federal State And Local Tax Expense Benefit CurrentFederalStateAndLocalTaxExpenseBenefit	-180800000	USD
CY2019	us-gaap	Current Federal State And Local Tax Expense Benefit CurrentFederalStateAndLocalTaxExpenseBenefit	-7800000	USD
CY2021	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	36100000	USD
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	38800000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	55300000	USD
CY2021	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	37800000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-142000000.0	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	47500000	USD
CY2021	us-gaap	Deferred Federal State And Local Tax Expense Benefit DeferredFederalStateAndLocalTaxExpenseBenefit	123400000	USD
CY2020	us-gaap	Deferred Federal State And Local Tax Expense Benefit DeferredFederalStateAndLocalTaxExpenseBenefit	192000000.0	USD
CY2019	us-gaap	Deferred Federal State And Local Tax Expense Benefit DeferredFederalStateAndLocalTaxExpenseBenefit	98000000.0	USD
CY2021	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	8300000	USD
CY2020	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	10400000	USD
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	2800000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	131700000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	202400000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	100800000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	169500000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	60400000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	148300000	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2021	aiz	Effective Income Tax Rate Reconciliation Tax Exempt Interest EffectiveIncomeTaxRateReconciliationTaxExemptInterest	0.002
CY2020	aiz	Effective Income Tax Rate Reconciliation Tax Exempt Interest EffectiveIncomeTaxRateReconciliationTaxExemptInterest	0.002
CY2019	aiz	Effective Income Tax Rate Reconciliation Tax Exempt Interest EffectiveIncomeTaxRateReconciliationTaxExemptInterest	0.005
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.010
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.014
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.010
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.007
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.007
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.008
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	-0.004
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	-0.005
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	0.001
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	-0.002
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.012
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.107
CY2021	aiz	Effective Income Tax Rate Reconciliation Net Operating Loss Carryback Percent Cares Act EffectiveIncomeTaxRateReconciliationNetOperatingLossCarrybackPercentCARESAct	0
CY2020	aiz	Effective Income Tax Rate Reconciliation Net Operating Loss Carryback Percent Cares Act EffectiveIncomeTaxRateReconciliationNetOperatingLossCarrybackPercentCARESAct	-0.137
CY2019	aiz	Effective Income Tax Rate Reconciliation Net Operating Loss Carryback Percent Cares Act EffectiveIncomeTaxRateReconciliationNetOperatingLossCarrybackPercentCARESAct	0
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.003
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.005
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.005
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.216
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.104
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.326
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	15600000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	12500000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	11800000	USD
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	600000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	500000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	500000	USD
CY2021	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	5900000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	2700000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	400000	USD
CY2021	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	3600000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	100000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	200000	USD
CY2021	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	0	USD
CY2020	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	0	USD
CY2019	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	0	USD
CY2021Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	18500000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	15600000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	12500000	USD
CY2021Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	19900000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	17900000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	14000000	USD
CY2021	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	-100000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	1500000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	700000	USD
CY2021Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	1700000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	1800000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	800000	USD
CY2021Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued	0	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued	800000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued	800000	USD
CY2021Q4	aiz	Deferred Tax Assets Policyholder And Separate Account Reserves DeferredTaxAssetsPolicyholderAndSeparateAccountReserves	642200000	USD
CY2020Q4	aiz	Deferred Tax Assets Policyholder And Separate Account Reserves DeferredTaxAssetsPolicyholderAndSeparateAccountReserves	720600000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	78800000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	53800000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Investments DeferredTaxAssetsInvestments	9400000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Investments DeferredTaxAssetsInvestments	7300000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	26300000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	32800000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits	17300000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits	25500000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	37500000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	29800000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Capital Loss Carryforwards DeferredTaxAssetsCapitalLossCarryforwards	300000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Capital Loss Carryforwards DeferredTaxAssetsCapitalLossCarryforwards	9800000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	47100000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	47600000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	858900000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	927200000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	25100000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	27600000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	833800000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	899600000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Policy Acquisition Cost DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost	1325800000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Policy Acquisition Cost DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost	1266500000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	90100000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	126500000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	101100000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	106000000.0	USD
CY2021Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	1517000000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	1499000000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	683200000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	599400000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	25100000	USD
CY2021	us-gaap	Deferred Policy Acquisition Costs Text Block1 DeferredPolicyAcquisitionCostsTextBlock1	Deferred Acquisition Costs <div style="text-indent:22.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Information about deferred acquisition costs is as follows as of the dates indicated:</span></div><div style="margin-top:5pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:99.853%"><tr><td style="width:1.0%"/><td style="width:59.222%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.637%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.532%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.637%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.532%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.640%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td colspan="15" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">December 31,</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2021</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Beginning balance</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">7,388.0 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,121.5 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,203.4 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 19pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Costs deferred</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,691.0 </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,022.9 </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,022.0 </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Amortization</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(3,268.0)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(2,756.4)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(2,103.9)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Ending balance</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">8,811.0 </span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">7,388.0 </span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,121.5 </span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div>
CY2020Q4	us-gaap	Deferred Policy Acquisition Costs DeferredPolicyAcquisitionCosts	7388000000	USD
CY2019Q4	us-gaap	Deferred Policy Acquisition Costs DeferredPolicyAcquisitionCosts	6121500000	USD
CY2018Q4	us-gaap	Deferred Policy Acquisition Costs DeferredPolicyAcquisitionCosts	4203400000	USD
CY2021	us-gaap	Deferred Policy Acquisition Costs Additions DeferredPolicyAcquisitionCostsAdditions	4691000000	USD
CY2020	us-gaap	Deferred Policy Acquisition Costs Additions DeferredPolicyAcquisitionCostsAdditions	4022900000	USD
CY2019	us-gaap	Deferred Policy Acquisition Costs Additions DeferredPolicyAcquisitionCostsAdditions	4022000000	USD
CY2021	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	3268000000	USD
CY2020	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	2756400000	USD
CY2019	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	2103900000	USD
CY2021Q4	us-gaap	Deferred Policy Acquisition Costs DeferredPolicyAcquisitionCosts	8811000000	USD
CY2020Q4	us-gaap	Deferred Policy Acquisition Costs DeferredPolicyAcquisitionCosts	7388000000	USD
CY2019Q4	us-gaap	Deferred Policy Acquisition Costs DeferredPolicyAcquisitionCosts	6121500000	USD
CY2021Q4	us-gaap	Land Land	10000000.0	USD
CY2020Q4	us-gaap	Land Land	10000000.0	USD
CY2021Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	917000000.0	USD
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	780500000	USD
CY2021Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	355600000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	334400000	USD
CY2021Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	561400000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	446100000	USD
CY2021	us-gaap	Depreciation Depreciation	73800000	USD
CY2020	us-gaap	Depreciation Depreciation	56100000	USD
CY2019	us-gaap	Depreciation Depreciation	51800000	USD
CY2021	us-gaap	Number Of Reporting Units NumberOfReportingUnits	4	reporting_unit
CY2019Q4	us-gaap	Goodwill Goodwill	2205400000	USD
CY2020	aiz	Goodwill Acquired During Period Including Purchase Accounting Adjustments GoodwillAcquiredDuringPeriodIncludingPurchaseAccountingAdjustments	374600000	USD
CY2020	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	9300000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	2589300000	USD
CY2021	aiz	Goodwill Acquired During Period Including Purchase Accounting Adjustments GoodwillAcquiredDuringPeriodIncludingPurchaseAccountingAdjustments	-10400000	USD
CY2021	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	-7300000	USD
CY2019	us-gaap	Present Value Of Future Insurance Profits Amortization Expense1 PresentValueOfFutureInsuranceProfitsAmortizationExpense1	1121000000	USD
CY2021	us-gaap	Present Value Of Future Insurance Profits Foreign Currency Translation Gain Loss PresentValueOfFutureInsuranceProfitsForeignCurrencyTranslationGainLoss	-900000	USD
CY2020	us-gaap	Present Value Of Future Insurance Profits Foreign Currency Translation Gain Loss PresentValueOfFutureInsuranceProfitsForeignCurrencyTranslationGainLoss	-5800000	USD
CY2021Q4	us-gaap	Goodwill Goodwill	2571600000	USD
CY2020Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	1405900000	USD
CY2021Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	1405900000	USD
CY2019Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	1268100000	USD
CY2020Q4	us-gaap	Value Of Business Acquired Voba ValueOfBusinessAcquiredVOBA	1152200000	USD
CY2019Q4	us-gaap	Value Of Business Acquired Voba ValueOfBusinessAcquiredVOBA	1993700000	USD
CY2018Q4	us-gaap	Value Of Business Acquired Voba ValueOfBusinessAcquiredVOBA	3140800000	USD
CY2021	us-gaap	Present Value Of Future Insurance Profit Experience Adjustment PresentValueOfFutureInsuranceProfitExperienceAdjustment	0	USD
CY2020	us-gaap	Present Value Of Future Insurance Profit Experience Adjustment PresentValueOfFutureInsuranceProfitExperienceAdjustment	0	USD
CY2019	us-gaap	Present Value Of Future Insurance Profit Experience Adjustment PresentValueOfFutureInsuranceProfitExperienceAdjustment	4000000.0	USD
CY2021	us-gaap	Present Value Of Future Insurance Profits Amortization Expense1 PresentValueOfFutureInsuranceProfitsAmortizationExpense1	567900000	USD
CY2020	us-gaap	Present Value Of Future Insurance Profits Amortization Expense1 PresentValueOfFutureInsuranceProfitsAmortizationExpense1	835700000	USD
CY2019	us-gaap	Present Value Of Future Insurance Profits Foreign Currency Translation Gain Loss PresentValueOfFutureInsuranceProfitsForeignCurrencyTranslationGainLoss	-22100000	USD
CY2021Q4	us-gaap	Value Of Business Acquired Voba ValueOfBusinessAcquiredVOBA	583400000	USD
CY2020Q4	us-gaap	Value Of Business Acquired Voba ValueOfBusinessAcquiredVOBA	1152200000	USD
CY2019Q4	us-gaap	Value Of Business Acquired Voba ValueOfBusinessAcquiredVOBA	1993700000	USD
CY2021Q4	us-gaap	Present Value Of Future Insurance Profits Amortization Expense Year One PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearOne	322500000	USD
CY2021Q4	us-gaap	Present Value Of Future Insurance Profits Amortization Expense Year Two PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearTwo	177800000	USD
CY2021Q4	us-gaap	Present Value Of Future Insurance Profits Amortization Expense Year Three PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearThree	76200000	USD
CY2021Q4	us-gaap	Present Value Of Future Insurance Profits Amortization Expense Year Four PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearFour	3300000	USD
CY2021Q4	us-gaap	Present Value Of Future Insurance Profits Amortization Expense Year Five PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearFive	1400000	USD
CY2021Q4	aiz	Present Valueof Future Insurance Profits Amortization Expense After Year Five PresentValueofFutureInsuranceProfitsAmortizationExpenseAfterYearFive	2200000	USD
CY2021Q4	us-gaap	Value Of Business Acquired Voba ValueOfBusinessAcquiredVOBA	583400000	USD
CY2021Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	1169700000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	450500000	USD
CY2021Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	719200000	USD
CY2020Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	1079200000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	383000000.0	USD
CY2020Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	696200000	USD
CY2020Q4	us-gaap	Indefinite Lived Intangible Assets Excluding Goodwill IndefiniteLivedIntangibleAssetsExcludingGoodwill	12100000	USD
CY2021Q4	us-gaap	Indefinite Lived Intangible Assets Excluding Goodwill IndefiniteLivedIntangibleAssetsExcludingGoodwill	12100000	USD
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	88900000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	73900000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	62200000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	98100000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	97900000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	93800000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	89600000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	78400000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	249300000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	707100000	USD
CY2021	us-gaap	Schedule Of Liability For Unpaid Claims And Claims Adjustment Expense ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense	<div style="margin-bottom:6pt;text-indent:22.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table provides a roll forward of the Company’s beginning and ending claims and benefits payable balances. Claims and benefits payable is the liability for unpaid loss and loss adjustment expenses and are comprised of case and IBNR reserves.</span></div><div style="margin-bottom:6pt;text-indent:22.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Since unpaid loss and loss adjustment expenses are estimates, the Company’s actual losses incurred may be more or less than the Company’s previously developed estimates, which is referred to as either unfavorable or favorable development, respectively.</span></div><div style="margin-bottom:6pt;text-indent:22.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The best estimate of ultimate loss and loss adjustment expenses is generally selected from a blend of methods that are applied consistently each period. There have been no significant changes in the methodologies and assumptions utilized in estimating the liability for unpaid loss and loss adjustment expenses for any of the periods presented. </span></div><div style="margin-top:5pt;text-align:center"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:99.853%"><tr><td style="width:1.0%"/><td style="width:59.222%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.637%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.532%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.637%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.532%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.640%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="15" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Years Ended December 31,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2021</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Claims and benefits payable, at beginning of year</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,610.3 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,613.1 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,606.3 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Less: Reinsurance ceded and other</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(849.4)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(855.1)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(874.2)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net claims and benefits payable, at beginning of year</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">760.9 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">758.0 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">732.1 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Incurred losses and loss adjustment expenses related to:</span></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Current year</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,202.2 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,305.4 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,401.6 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Prior years</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(6.5)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(40.5)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(15.9)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total incurred losses and loss adjustment expenses</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,195.7 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,264.9 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,385.7 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Paid losses and loss adjustment expenses related to:</span></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Current year</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,679.2 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,770.6 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,857.3 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Prior years</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">505.1 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">491.4 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">502.5 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total paid losses and loss adjustment expenses</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,184.3 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,262.0 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,359.8 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Transfer to liabilities held for sale (Note 4)</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(2.0)</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">— </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">— </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net claims and benefits payable, at end of year</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">770.3 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">760.9 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">758.0 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Plus: Reinsurance ceded and other (1)</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">825.6 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">849.4 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">855.1 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Claims and benefits payable, at end of year (1)</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,595.9 </span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,610.3 </span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,613.1 </span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="padding-left:18pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%">(1)</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%;padding-left:8.68pt">Includes reinsurance recoverables and claims and benefits payable of $143.8 million, $95.8 million and $86.8 million as of December 31, 2021, 2020 and 2019, respectively, which were ceded to the U.S. government. The Company acts as an administrator for the U.S. government under the voluntary National Flood Insurance Program. </span></div><div style="padding-left:18pt"><span><br/></span></div><div style="margin-bottom:6pt;text-indent:22.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A comparison of net (favorable) unfavorable prior year development is shown below across the Company’s current and former segments and businesses. </span></div><div style="margin-top:5pt;text-align:center"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:99.707%"><tr><td style="width:1.0%"/><td style="width:47.140%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:15.468%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.533%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:15.762%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.533%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:15.764%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="15" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Prior Year Incurred Loss Development for the Years Ending December 31, </span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2021</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Global Lifestyle</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(35.2)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(27.6)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(24.0)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Global Housing</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">36.5 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(8.0)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13.6 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">All Other</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(7.8)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(4.9)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(5.5)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(6.5)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(40.5)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(15.9)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div>
CY2020Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	1610300000	USD
CY2019Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	1613100000	USD
CY2018Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	1606300000	USD
CY2020Q4	aiz	Reinsurance Cededand Othercasereservesand Ibnr ReinsuranceCededandOthercasereservesandIBNR	849400000	USD
CY2019Q4	aiz	Reinsurance Cededand Othercasereservesand Ibnr ReinsuranceCededandOthercasereservesandIBNR	855100000	USD
CY2018Q4	aiz	Reinsurance Cededand Othercasereservesand Ibnr ReinsuranceCededandOthercasereservesandIBNR	874200000	USD
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	760900000	USD
CY2019Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	758000000.0	USD
CY2018Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	732100000	USD
CY2021	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	2202200000	USD
CY2020	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	2305400000	USD
CY2019	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	2401600000	USD
CY2021	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-6500000	USD
CY2020	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-40500000	USD
CY2019	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-15900000	USD
CY2021	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	2195700000	USD
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	2264900000	USD
CY2019	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	2385700000	USD
CY2021	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	1679200000	USD
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	1770600000	USD
CY2021Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	770300000	USD
CY2019	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	1857300000	USD
CY2020	aiz	Liability For Unpaid Claims And Claims Adjustment Expense Transfer To Liabilities Held For Sale LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTransferToLiabilitiesHeldForSale	0	USD
CY2019	aiz	Liability For Unpaid Claims And Claims Adjustment Expense Transfer To Liabilities Held For Sale LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTransferToLiabilitiesHeldForSale	0	USD
CY2021	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	505100000	USD
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	491400000	USD
CY2019	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	502500000	USD
CY2021	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	2184300000	USD
CY2020	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	2262000000	USD
CY2019	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	2359800000	USD
CY2021	aiz	Liability For Unpaid Claims And Claims Adjustment Expense Transfer To Liabilities Held For Sale LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTransferToLiabilitiesHeldForSale	-2000000.0	USD
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	760900000	USD
CY2019Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	758000000.0	USD
CY2021Q4	aiz	Reinsurance Cededand Othercasereservesand Ibnr ReinsuranceCededandOthercasereservesandIBNR	825600000	USD
CY2020Q4	aiz	Reinsurance Cededand Othercasereservesand Ibnr ReinsuranceCededandOthercasereservesandIBNR	849400000	USD
CY2019Q4	aiz	Reinsurance Cededand Othercasereservesand Ibnr ReinsuranceCededandOthercasereservesandIBNR	855100000	USD
CY2021Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	1595900000	USD
CY2020Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	1610300000	USD
CY2019Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	1613100000	USD
CY2021	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-6500000	USD
CY2020	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-40500000	USD
CY2019	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-15900000	USD
CY2021Q4	us-gaap	Shortduration Insurance Contracts Liability For Unpaid Claims And Allocated Claim Adjustment Expense Net ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet	761200000	USD
CY2021Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	737800000	USD
CY2021Q4	us-gaap	Shortduration Insurance Contracts Liability For Unpaid Claims And Claims Adjustment Expense Accumulated Unallocated Claim Adjustment Expense ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense	9200000	USD
CY2021Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	1595900000	USD
CY2021Q4	us-gaap	Reinsurance Recoverables ReinsuranceRecoverables	6178900000	USD
CY2020Q4	us-gaap	Reinsurance Recoverables ReinsuranceRecoverables	6605400000	USD
CY2021Q4	us-gaap	Reinsurance Recoverables Gross ReinsuranceRecoverablesGross	6183900000	USD
CY2021Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	5000000.0	USD
CY2021Q4	us-gaap	Reinsurance Recoverables ReinsuranceRecoverables	6178900000	USD
CY2021	us-gaap	Direct Premiums Earned DirectPremiumsEarned	15910100000	USD
CY2020	us-gaap	Direct Premiums Earned DirectPremiumsEarned	14912000000	USD
CY2019	us-gaap	Direct Premiums Earned DirectPremiumsEarned	14021200000	USD
CY2021	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	168500000	USD
CY2020	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	133300000	USD
CY2019	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	212800000	USD
CY2021	us-gaap	Ceded Premiums Earned CededPremiumsEarned	7506500000	USD
CY2020	us-gaap	Ceded Premiums Earned CededPremiumsEarned	6769500000	USD
CY2019	us-gaap	Ceded Premiums Earned CededPremiumsEarned	6275200000	USD
CY2021	us-gaap	Premiums Earned Net PremiumsEarnedNet	8572100000	USD
CY2020	us-gaap	Premiums Earned Net PremiumsEarnedNet	8275800000	USD
CY2019	us-gaap	Premiums Earned Net PremiumsEarnedNet	7958800000	USD
CY2021	us-gaap	Policyholder Benefits And Claims Incurred Gross PolicyholderBenefitsAndClaimsIncurredGross	6271400000	USD
CY2020	us-gaap	Policyholder Benefits And Claims Incurred Gross PolicyholderBenefitsAndClaimsIncurredGross	5672900000	USD
CY2019	us-gaap	Policyholder Benefits And Claims Incurred Gross PolicyholderBenefitsAndClaimsIncurredGross	5534900000	USD
CY2021	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Assumed ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed	139100000	USD
CY2020	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Assumed ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed	122300000	USD
CY2019	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Assumed ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed	212900000	USD
CY2021	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	4214800000	USD
CY2020	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	3530300000	USD
CY2019	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	3362100000	USD
CY2021	us-gaap	Policyholder Benefits And Claims Incurred Net PolicyholderBenefitsAndClaimsIncurredNet	2195700000	USD
CY2020	us-gaap	Policyholder Benefits And Claims Incurred Net PolicyholderBenefitsAndClaimsIncurredNet	2264900000	USD
CY2019	us-gaap	Policyholder Benefits And Claims Incurred Net PolicyholderBenefitsAndClaimsIncurredNet	2385700000	USD
CY2021Q4	us-gaap	Assets Held In Trust AssetsHeldInTrust	0	USD
CY2020Q4	us-gaap	Assets Held In Trust AssetsHeldInTrust	168400000	USD
CY2021Q4	us-gaap	Unsecured Debt UnsecuredDebt	2202500000	USD
CY2020Q4	us-gaap	Unsecured Debt UnsecuredDebt	2252900000	USD
CY2021	us-gaap	Interest Expense InterestExpense	111800000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	3000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	3000000	USD
CY2020	us-gaap	Interest Expense InterestExpense	104500000	USD
CY2019	us-gaap	Interest Expense InterestExpense	110600000	USD
CY2021Q4	us-gaap	Interest Payable Current And Noncurrent InterestPayableCurrentAndNoncurrent	33900000	USD
CY2020Q4	us-gaap	Interest Payable Current And Noncurrent InterestPayableCurrentAndNoncurrent	31800000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	3000000	USD
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	57967808	shares
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	59945893	shares
CY2018Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	61908979	shares
CY2021	us-gaap	Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	214116	shares
CY2020	us-gaap	Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	213569	shares
CY2019	us-gaap	Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	248333	shares
CY2021	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	91845	shares
CY2020	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	157155	shares
CY2019	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	117581	shares
CY2021	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	113555	shares
CY2020	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	90166	shares
CY2019	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	88498	shares
CY2021	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	5337122	shares
CY2020	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	2438975	shares
CY2019	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	2417498	shares
CY2021Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	55754113	shares
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	57967808	shares
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	59945893	shares
CY2021	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	4700000	USD
CY2021Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	800000000	shares
CY2021Q1	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	600000000	USD
CY2021Q2	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	900000000	USD
CY2021	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	5337122	shares
CY2021	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	844400000	USD
CY2021Q4	us-gaap	Stock Repurchase Program Remaining Authorized Repurchase Amount1 StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1	842100000	USD
CY2020	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	2438975	shares
CY2019	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	2417498	shares
CY2020	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	299800000	USD
CY2019	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	274900000	USD
CY2020	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	18700000	USD
CY2021	aiz	Forfeiture Rate ForfeitureRate	0.05
CY2019	aiz	Forfeiture Rate ForfeitureRate	0.05
CY2020	aiz	Forfeiture Rate ForfeitureRate	0.05
CY2020Q4	us-gaap	Statutory Accounting Practices Statutory Capital And Surplus Balance StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance	2013100000	USD
CY2021	aiz	Statutory Accounting Practices Statutory Surplus Percentage StatutoryAccountingPracticesStatutorySurplusPercentage	0.10
CY2019	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	11300000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-229600000	USD
CY2021	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	630200000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-859800000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	274200000	USD
CY2020	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	-24100000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	298300000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	578200000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	566900000	USD
CY2021	us-gaap	Statutory Accounting Practices Statutory Net Income Amount StatutoryAccountingPracticesStatutoryNetIncomeAmount	486600000	USD
CY2020	us-gaap	Statutory Accounting Practices Statutory Net Income Amount StatutoryAccountingPracticesStatutoryNetIncomeAmount	543800000	USD
CY2019	us-gaap	Statutory Accounting Practices Statutory Net Income Amount StatutoryAccountingPracticesStatutoryNetIncomeAmount	418000000.0	USD
CY2021Q4	us-gaap	Statutory Accounting Practices Statutory Capital And Surplus Balance StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance	1649400000	USD
CY2021Q4	us-gaap	Statutory Accounting Practices Statutory Amount Available For Dividend Payments Without Regulatory Approval StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval	475300000	USD
CY2021	aiz	Statutory Accounting Practices Risk Based Capital Requirements Authorized Control Level StatutoryAccountingPracticesRiskBasedCapitalRequirementsAuthorizedControlLevel	1
CY2021	aiz	Percentage Of Pension Plan Deficit Added To Amount Of Service Cost PercentageOfPensionPlanDeficitAddedToAmountOfServiceCost	0.15
CY2021	us-gaap	Pension Contributions PensionContributions	0	USD
CY2021Q4	us-gaap	Defined Benefit Plan Expected Future Employer Contributions Next Fiscal Year DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear	0	USD
CY2021	aiz	Numberofbondsinyieldcurvethatisutilizedinthecashflowanalysisforthepensionplan Numberofbondsinyieldcurvethatisutilizedinthecashflowanalysisforthepensionplan	228	security
CY2021	aiz	Defined Benefit Plan Actual Return On Plan Assets Percentage DefinedBenefitPlanActualReturnOnPlanAssetsPercentage	0.024
CY2020	aiz	Defined Benefit Plan Actual Return On Plan Assets Percentage DefinedBenefitPlanActualReturnOnPlanAssetsPercentage	0.109
CY2019	aiz	Defined Benefit Plan Actual Return On Plan Assets Percentage DefinedBenefitPlanActualReturnOnPlanAssetsPercentage	0.163
CY2019	us-gaap	Undistributed Earnings UndistributedEarnings	132100000	USD
CY2019	us-gaap	Undistributed Earnings Diluted UndistributedEarningsDiluted	132100000	USD
CY2021	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	40300000	USD
CY2020	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	41300000	USD
CY2019	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	38400000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	613500000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	520400000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	306400000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	0	USD
CY2020	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	900000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	4200000	USD
CY2021	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	613500000	USD
CY2020	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	519500000	USD
CY2019	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	302200000	USD
CY2021	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	4700000	USD
CY2020	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	18700000	USD
CY2019	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	18700000	USD
CY2021	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Diluted NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted	608800000	USD
CY2021	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Basic NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic	608800000	USD
CY2020	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Basic NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic	500800000	USD
CY2020	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Diluted NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted	500800000	USD
CY2019	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Basic NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic	283500000	USD
CY2019	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Diluted NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted	283500000	USD
CY2021	us-gaap	Dividends Common Stock DividendsCommonStock	157600000	USD
CY2020	us-gaap	Dividends Common Stock DividendsCommonStock	154600000	USD
CY2019	us-gaap	Dividends Common Stock DividendsCommonStock	151400000	USD
CY2021	us-gaap	Undistributed Earnings Diluted UndistributedEarningsDiluted	451200000	USD
CY2021	us-gaap	Undistributed Earnings UndistributedEarnings	451200000	USD
CY2020	us-gaap	Undistributed Earnings Diluted UndistributedEarningsDiluted	346200000	USD
CY2020	us-gaap	Undistributed Earnings UndistributedEarnings	346200000	USD
CY2021	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Diluted NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted	608800000	USD
CY2021	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Basic NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic	608800000	USD
CY2020	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Basic NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic	500800000	USD
CY2020	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Diluted NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted	500800000	USD
CY2019	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Basic NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic	283500000	USD
CY2019	us-gaap	Net Income Loss From Continuing Operations Available To Common Shareholders Diluted NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted	283500000	USD
CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	758900000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-77700000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	80400000	USD
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1367700000	USD
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	1367700000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	423100000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	423100000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	363900000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	363900000	USD
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	59140861	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	60114670	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	61942969	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	60123694	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	63179938	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	62313468	shares
CY2021	us-gaap	Earnings Per Share Basic Distributed EarningsPerShareBasicDistributed	2.66
CY2020	us-gaap	Earnings Per Share Basic Distributed EarningsPerShareBasicDistributed	2.57
CY2019	us-gaap	Earnings Per Share Basic Distributed EarningsPerShareBasicDistributed	2.44
CY2021	us-gaap	Earnings Per Share Basic Undistributed EarningsPerShareBasicUndistributed	7.63
CY2020	us-gaap	Earnings Per Share Basic Undistributed EarningsPerShareBasicUndistributed	5.76
CY2019	us-gaap	Earnings Per Share Basic Undistributed EarningsPerShareBasicUndistributed	2.14
CY2021	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	10.29
CY2020	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	8.33
CY2019	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	4.58
CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	12.84
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	-1.29
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	1.29
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	23.13
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	7.04
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.87
CY2021	us-gaap	Earnings Per Share Diluted Distributed EarningsPerShareDilutedDistributed	2.62
CY2020	us-gaap	Earnings Per Share Diluted Distributed EarningsPerShareDilutedDistributed	2.45
CY2019	us-gaap	Earnings Per Share Diluted Distributed EarningsPerShareDilutedDistributed	2.43
CY2021	us-gaap	Earnings Per Share Diluted Undistributed EarningsPerShareDilutedUndistributed	7.58
CY2020	us-gaap	Earnings Per Share Diluted Undistributed EarningsPerShareDilutedUndistributed	5.77
CY2019	us-gaap	Earnings Per Share Diluted Undistributed EarningsPerShareDilutedUndistributed	2.13
CY2021	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	10.20
CY2020	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	8.22
CY2019	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	4.56
CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	12.63
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	-1.23
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	1.28
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	22.83
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.99
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.84
CY2021Q1	us-gaap	Revenues Revenues	2432600000	USD
CY2021Q2	us-gaap	Revenues Revenues	2542300000	USD
CY2021Q3	us-gaap	Revenues Revenues	2637800000	USD
CY2021Q4	us-gaap	Revenues Revenues	2574900000	USD
CY2021Q4	us-gaap	Revenues Revenues	2574900000	USD
CY2021Q4	us-gaap	Revenues Revenues	2574900000	USD
CY2021Q4	us-gaap	Revenues Revenues	2574900000	USD
CY2021Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	193100000	USD
CY2021Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	236600000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	191500000	USD
CY2021Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	161800000	USD
CY2021Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	161800000	USD
CY2021Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	161800000	USD
CY2021Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	161800000	USD
CY2021Q1	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	148500000	USD
CY2021Q2	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	184700000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	153600000	USD
CY2021Q4	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	126700000	USD
CY2021Q1	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	158300000	USD
CY2021Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	158300000	USD
CY2021Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	203400000	USD
CY2021Q2	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	203400000	USD
CY2021Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	882400000	USD
CY2021Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	882400000	USD
CY2021Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	123600000	USD
CY2021Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	123600000	USD
CY2021Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	123600000	USD
CY2021Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	123600000	USD
CY2021Q4	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	123600000	USD
CY2021Q1	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Basic IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareBasic	3.26
CY2021Q2	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Basic IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareBasic	3.88
CY2021Q3	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Basic IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareBasic	3.24
CY2021Q4	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Basic IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareBasic	2.82
CY2021Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.43
CY2021Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	3.03
CY2021Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.60
CY2021Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.21
CY2021Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.67
CY2021Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.34
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	14.92
CY2021Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.16
CY2021Q1	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Diluted IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareDiluted	3.13
CY2021Q2	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Diluted IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareDiluted	3.86
CY2021Q3	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Diluted IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareDiluted	3.22
CY2021Q4	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Diluted IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareDiluted	2.80
CY2021Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.41
CY2021Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	3.01
CY2021Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.58
CY2021Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.20
CY2021Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.64
CY2021Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.32
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	14.83
CY2021Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.14
CY2020Q1	us-gaap	Revenues Revenues	2448700000	USD
CY2020Q2	us-gaap	Revenues Revenues	2352000000	USD
CY2020Q3	us-gaap	Revenues Revenues	2376700000	USD
CY2020Q4	us-gaap	Revenues Revenues	2418100000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	100100000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	209300000	USD
CY2020Q3	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Basic IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareBasic	1.87
CY2020Q4	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Basic IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareBasic	2.68
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	112500000	USD
CY2020Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	158900000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	148600000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	164700000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	88000000.0	USD
CY2020Q4	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	119100000	USD
CY2020Q1	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	150000000.0	USD
CY2020Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	150000000.0	USD
CY2020Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	173500000	USD
CY2020Q2	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	173500000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	-34900000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-34900000	USD
CY2020Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	134500000	USD
CY2020Q4	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	134500000	USD
CY2020Q1	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Basic IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareBasic	1.65
CY2020Q2	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Basic IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareBasic	3.47
CY2020Q1	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Diluted IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareDiluted	1.57
CY2020Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.36
CY2020Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.65
CY2020Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.39
CY2020Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.93
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.48
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.87
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.58
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.27
CY2020Q2	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Diluted IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareDiluted	3.30
CY2020Q3	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Diluted IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareDiluted	1.86
CY2020Q4	aiz	Income Loss From Continuing Operations Before Provision For Income Taxes Per Share Diluted IncomeLossFromContinuingOperationsBeforeProvisionForIncomeTaxesPerShareDiluted	2.55
CY2020Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.32
CY2020Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.59
CY2020Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.38
CY2020Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.91
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	67000000	USD
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	47700000	USD
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.43
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.81
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.58
CY2020Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.23
CY2020Q1	aiz	Cares Act Tax Benefit CARESActTaxBenefit	79300000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	60500000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	77700000	USD
CY2021	us-gaap	Operating Lease Cost OperatingLeaseCost	23100000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	23800000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	22100000	USD
CY2021	us-gaap	Operating Lease Payments OperatingLeasePayments	23800000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	22700000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	21300000	USD
CY2021Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P6Y
CY2021Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.043
CY2020Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	7600000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P6Y
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.040
CY2021	us-gaap	Short Term Lease Cost ShortTermLeaseCost	2900000	USD
CY2020	us-gaap	Short Term Lease Cost ShortTermLeaseCost	3400000	USD
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	4200000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	17400000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	13800000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	10600000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	6500000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	5000000.0	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	16100000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	69400000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	8900000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	60500000	USD
CY2021Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	7200000	USD
CY2021Q4	us-gaap	Summary Of Investments Other Than Investments In Related Parties Cost SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCost	8242400000	USD
CY2021Q4	us-gaap	Summary Of Investments Other Than Investments In Related Parties Carrying Amount SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCarryingAmount	8671600000	USD
CY2021Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	8811000000	USD
CY2021Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	413200000	USD
CY2021Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	18623700000	USD
CY2021Q4	us-gaap	Supplementary Insurance Information Other Policy Claims And Benefits Payable SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable	1595900000	USD
CY2021	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	8572100000	USD
CY2021	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	314400000	USD
CY2021	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	2195700000	USD
CY2021	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	3268000000	USD
CY2021	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	3808400000	USD
CY2021	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	2735400000	USD
CY2020Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	7388000000	USD
CY2020Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	1358500000	USD
CY2020Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	17293100000	USD
CY2020Q4	us-gaap	Supplementary Insurance Information Other Policy Claims And Benefits Payable SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable	1610300000	USD
CY2020	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	8275800000	USD
CY2020	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	285600000	USD
CY2020	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	2264900000	USD
CY2020	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	2756400000	USD
CY2020	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	3888900000	USD
CY2020	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	2878800000	USD
CY2019Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	6121500000	USD
CY2019Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	1372500000	USD
CY2019Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	16560200000	USD
CY2019Q4	us-gaap	Supplementary Insurance Information Other Policy Claims And Benefits Payable SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable	1613100000	USD
CY2019	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	7958800000	USD
CY2019	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	383200000	USD
CY2019	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	2385700000	USD
CY2019	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	2103900000	USD
CY2019	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	4482800000	USD
CY2019	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	2917600000	USD
CY2021Q4	srt	Life Insurance In Force Gross LifeInsuranceInForceGross	7431300000	USD
CY2021Q4	srt	Life Insurance In Force Ceded LifeInsuranceInForceCeded	4953800000	USD
CY2021Q4	srt	Life Insurance In Force Assumed LifeInsuranceInForceAssumed	2500000	USD
CY2021Q4	srt	Life Insurance In Force Net LifeInsuranceInForceNet	2480000000	USD
CY2021Q4	srt	Life Insurance In Force Percentage Assumed To Net LifeInsuranceInForcePercentageAssumedToNet	0.001
CY2021	us-gaap	Direct Premiums Earned DirectPremiumsEarned	15910100000	USD
CY2021	us-gaap	Ceded Premiums Earned CededPremiumsEarned	7506500000	USD
CY2021	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	168500000	USD
CY2021	us-gaap	Premiums Earned Net PremiumsEarnedNet	8572100000	USD
CY2021	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.020
CY2021	us-gaap	Policyholder Benefits And Claims Incurred Gross PolicyholderBenefitsAndClaimsIncurredGross	6271400000	USD
CY2021	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	4214800000	USD
CY2021	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Assumed ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed	139100000	USD
CY2021	us-gaap	Policyholder Benefits And Claims Incurred Net PolicyholderBenefitsAndClaimsIncurredNet	2195700000	USD
CY2021	aiz	Benefits Percentage Of Amount Assumed To Net BenefitsPercentageOfAmountAssumedToNet	0.063
CY2020Q4	srt	Life Insurance In Force Gross LifeInsuranceInForceGross	8270100000	USD
CY2020Q4	srt	Life Insurance In Force Ceded LifeInsuranceInForceCeded	5842400000	USD
CY2020Q4	srt	Life Insurance In Force Assumed LifeInsuranceInForceAssumed	3800000	USD
CY2020Q4	srt	Life Insurance In Force Net LifeInsuranceInForceNet	2431500000	USD
CY2020Q4	srt	Life Insurance In Force Percentage Assumed To Net LifeInsuranceInForcePercentageAssumedToNet	0.002
CY2020	us-gaap	Direct Premiums Earned DirectPremiumsEarned	14912000000	USD
CY2020	us-gaap	Ceded Premiums Earned CededPremiumsEarned	6769500000	USD
CY2020	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	133300000	USD
CY2020	us-gaap	Premiums Earned Net PremiumsEarnedNet	8275800000	USD
CY2020	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.016
CY2020	us-gaap	Policyholder Benefits And Claims Incurred Gross PolicyholderBenefitsAndClaimsIncurredGross	5672900000	USD
CY2020	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	3530300000	USD
CY2020	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Assumed ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed	122300000	USD
CY2020	us-gaap	Policyholder Benefits And Claims Incurred Net PolicyholderBenefitsAndClaimsIncurredNet	2264900000	USD
CY2020	aiz	Benefits Percentage Of Amount Assumed To Net BenefitsPercentageOfAmountAssumedToNet	0.054
CY2019Q4	srt	Life Insurance In Force Gross LifeInsuranceInForceGross	9026100000	USD
CY2019Q4	srt	Life Insurance In Force Ceded LifeInsuranceInForceCeded	5560400000	USD
CY2019Q4	srt	Life Insurance In Force Assumed LifeInsuranceInForceAssumed	2800000	USD
CY2019Q4	srt	Life Insurance In Force Net LifeInsuranceInForceNet	3468500000	USD
CY2019Q4	srt	Life Insurance In Force Percentage Assumed To Net LifeInsuranceInForcePercentageAssumedToNet	0.001
CY2019	us-gaap	Direct Premiums Earned DirectPremiumsEarned	14021200000	USD
CY2019	us-gaap	Ceded Premiums Earned CededPremiumsEarned	6275200000	USD
CY2019	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	212800000	USD
CY2019	us-gaap	Premiums Earned Net PremiumsEarnedNet	7958800000	USD
CY2019	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.027
CY2019	us-gaap	Policyholder Benefits And Claims Incurred Gross PolicyholderBenefitsAndClaimsIncurredGross	5534900000	USD
CY2019	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	3362100000	USD
CY2019	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Assumed ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed	212900000	USD
CY2019	us-gaap	Policyholder Benefits And Claims Incurred Net PolicyholderBenefitsAndClaimsIncurredNet	2385700000	USD
CY2019	aiz	Benefits Percentage Of Amount Assumed To Net BenefitsPercentageOfAmountAssumedToNet	0.089
CY2020Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	71500000	USD
CY2021	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	-6000000.0	USD
CY2021	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	-300000	USD
CY2021	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	22100000	USD
CY2021Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	43100000	USD
CY2019Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	96200000	USD
CY2020	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	-39100000	USD
CY2020	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	22200000	USD
CY2020	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	7800000	USD
CY2020Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	71500000	USD
CY2018Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	44500000	USD
CY2019	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	54000000.0	USD
CY2019	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	0	USD
CY2019	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	2300000	USD
CY2019Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	96200000	USD

Files In Submission

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$AIZ
ASSURANT, INC. Stock $aiz

2021 Q4 Form 10-K Financial Statement

#000126723822000006 Filed on February 22, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AIZ ASSURANT, INC. Stock $aiz

2021 Q4 Form 10-K Financial Statement

#000126723822000006 Filed on February 22, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AIZ
ASSURANT, INC. Stock $aiz