$WTM
WHITE MOUNTAINS INSURANCE GROUP LTD Stock $wtm

$wtm Overview Financials Valuation SEC Filings Company Website

2021 Q4 Form 10-K Financial Statement

#000077686722000002 Filed on February 28, 2022

Income Statement

Concept	2021 Q4	2021	2020 Q4
Revenue	$350.0M	$944.8M	$520.8M
YoY Change	-32.8%	-19.98%	197.09%
Cost Of Revenue		$69.30M
YoY Change		513.27%
Gross Profit		$875.5M
YoY Change		-25.13%
Gross Profit Margin		92.67%
Selling, General & Admin	$167.7M	$632.4M	$144.0M
YoY Change	16.46%	35.24%	31.75%
% of Gross Profit		72.23%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$38.90M	$63.60M	$14.40M
YoY Change	170.14%	46.54%	54.84%
% of Gross Profit		7.26%
Operating Expenses	$302.0M	$1.174B	$156.9M
YoY Change	92.48%	133.32%	33.65%
Operating Profit		-$298.8M
YoY Change		-144.86%
Interest Expense	-$11.30M	-$43.80M	-$6.600M
YoY Change	71.21%	67.18%	371.43%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$36.70M	-$302.0M	$357.3M
YoY Change	-89.73%	-146.81%	532.39%
Income Tax	-$3.300M	$38.60M	-$117.6M
% Of Pretax Income	-8.99%		-32.91%
Net Earnings	$32.80M	-$321.9M	$489.2M
YoY Change	-93.3%	-148.52%	703.28%
Net Earnings / Revenue	9.37%	-34.07%	93.93%
Basic Earnings Per Share		-$89.46	$157.70
Diluted Earnings Per Share	$10.49M	-$89.46	$157.70
COMMON SHARES
Basic Shares Outstanding	3.018M shares	3.043M shares	3.102M shares
Diluted Shares Outstanding		3.043M shares

Balance Sheet

Concept	2021 Q4	2021	2020 Q4
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$147.7M		$84.60M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets			$3.000M
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$42.20M	$42.20M	$38.00M
YoY Change	11.05%	11.05%	65.22%
Goodwill	$142.3M		$525.5M
YoY Change	-72.92%		33.14%
Intangibles	$198.2M
YoY Change
Long-Term Investments	$4.265B	$4.265B	$2.939B
YoY Change	45.13%	45.13%	-0.27%
Other Assets	$16.10M	$16.10M	$649.0M
YoY Change	-97.52%	-97.52%	21533.33%
Total Long-Term Assets			$4.828B
YoY Change
TOTAL ASSETS
Total Short-Term Assets			$3.000M
Total Long-Term Assets			$4.828B
Total Assets	$7.001B	$7.001B	$4.831B
YoY Change	44.9%	44.91%	21.29%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$118.4M	$118.4M	$134.0M
YoY Change	-11.64%	-11.64%	34.0%
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	$118.4M	$118.4M	$134.0M
YoY Change	-11.64%	-11.64%	34.0%
LONG-TERM LIABILITIES
Long-Term Debt	$693.0M	$693.0M	$376.0M
YoY Change	84.31%	84.31%	32.39%
Other Long-Term Liabilities	$267.7M	$267.7M	$152.0M
YoY Change	76.12%	76.12%	-1.94%
Total Long-Term Liabilities	$960.7M	$960.7M	$528.0M
YoY Change	81.95%	81.95%	20.27%
TOTAL LIABILITIES
Total Short-Term Liabilities	$118.4M	$118.4M	$134.0M
Total Long-Term Liabilities	$960.7M	$960.7M	$528.0M
Total Liabilities	$3.296B	$3.453B	$1.014B
YoY Change	225.21%	273.25%	20.87%
SHAREHOLDERS EQUITY
Retained Earnings	$2.958B		$3.311B
YoY Change	-10.68%		23.9%
Common Stock	$588.9M		$595.2M
YoY Change	-1.06%		-0.18%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$3.548B	$3.548B	$3.906B
YoY Change
Total Liabilities & Shareholders Equity	$7.001B	$7.001B	$4.831B
YoY Change	44.9%	44.91%	21.29%

Cashflow Statement

Concept	2021 Q4	2021	2020 Q4
OPERATING ACTIVITIES
Net Income	$32.80M	-$321.9M	$489.2M
YoY Change	-93.3%	-148.52%	703.28%
Depreciation, Depletion And Amortization	$38.90M	$63.60M	$14.40M
YoY Change	170.14%	46.54%	54.84%
Cash From Operating Activities	-$7.400M	$38.60M	-$72.80M
YoY Change	-89.84%	-163.7%	51.67%
INVESTING ACTIVITIES
Capital Expenditures
YoY Change
Acquisitions		-$10.60M
YoY Change
Other Investing Activities	-$38.90M	-$2.500M	$36.60M
YoY Change	-206.28%	-725.0%	6000.0%
Cash From Investing Activities	-$38.90M	-$208.3M	$36.60M
YoY Change	-206.28%	-422.45%	6000.0%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net		$100.1M
YoY Change		27.52%
Debt Paid & Issued, Net		$120.1M
YoY Change
Cash From Financing Activities	-4.700M	$217.6M	35.20M
YoY Change	-113.35%	344.08%	-39.1%
NET CHANGE
Cash From Operating Activities	-7.400M	$38.60M	-72.80M
Cash From Investing Activities	-38.90M	-$208.3M	36.60M
Cash From Financing Activities	-4.700M	$217.6M	35.20M
Net Change In Cash	-51.00M	$48.10M	-1.000M
YoY Change	5000.0%	-4.18%	-109.62%
FREE CASH FLOW
Cash From Operating Activities	-$7.400M	$38.60M	-$72.80M
Capital Expenditures
Free Cash Flow
YoY Change

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
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CY2021	dei	Entity File Number EntityFileNumber	1-8993
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CY2021	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	D0
CY2021	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	94-2708455
CY2021	dei	Entity Address Address Line1 EntityAddressAddressLine1	23 South Main Street, Suite 3B
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CY2021	dei	Trading Symbol TradingSymbol	WTM
CY2021	dei	Security Exchange Name SecurityExchangeName	NYSE
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CY2019	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	35800000	USD
CY2021	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	41800000	USD
CY2020	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	5800000	USD
CY2019	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	3100000	USD
CY2021	us-gaap	Increase Decrease In Funds Held Under Reinsurance Agreements IncreaseDecreaseInFundsHeldUnderReinsuranceAgreements	104200000	USD
CY2020	us-gaap	Increase Decrease In Funds Held Under Reinsurance Agreements IncreaseDecreaseInFundsHeldUnderReinsuranceAgreements	0	USD
CY2019	us-gaap	Increase Decrease In Funds Held Under Reinsurance Agreements IncreaseDecreaseInFundsHeldUnderReinsuranceAgreements	0	USD
CY2021	wtm	Increase Decrease In Restricted Cash Operating Activities IncreaseDecreaseInRestrictedCashOperatingActivities	-15300000	USD
CY2020	wtm	Increase Decrease In Restricted Cash Operating Activities IncreaseDecreaseInRestrictedCashOperatingActivities	-22100000	USD
CY2019	wtm	Increase Decrease In Restricted Cash Operating Activities IncreaseDecreaseInRestrictedCashOperatingActivities	-6300000	USD
CY2021	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	178900000	USD
CY2020	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	118300000	USD
CY2019	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	118400000	USD
CY2021	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-24200000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-30900000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-20400000	USD
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	38600000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-60600000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-120500000	USD
CY2021	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	-54300000	USD
CY2020	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	-58700000	USD
CY2019	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	-21900000	USD
CY2021	wtm	Proceeds From Sale Of Trading Fixed Maturity And Convertible Fixed Maturity Investments ProceedsFromSaleOfTradingFixedMaturityAndConvertibleFixedMaturityInvestments	283600000	USD
CY2020	wtm	Proceeds From Sale Of Trading Fixed Maturity And Convertible Fixed Maturity Investments ProceedsFromSaleOfTradingFixedMaturityAndConvertibleFixedMaturityInvestments	390000000.0	USD
CY2019	wtm	Proceeds From Sale Of Trading Fixed Maturity And Convertible Fixed Maturity Investments ProceedsFromSaleOfTradingFixedMaturityAndConvertibleFixedMaturityInvestments	334300000	USD
CY2021	wtm	Proceeds From Maturities Of Trading Fixed Maturity And Convertible Fixed Maturity Investments ProceedsFromMaturitiesOfTradingFixedMaturityAndConvertibleFixedMaturityInvestments	199000000.0	USD
CY2020	wtm	Proceeds From Maturities Of Trading Fixed Maturity And Convertible Fixed Maturity Investments ProceedsFromMaturitiesOfTradingFixedMaturityAndConvertibleFixedMaturityInvestments	180400000	USD
CY2019	wtm	Proceeds From Maturities Of Trading Fixed Maturity And Convertible Fixed Maturity Investments ProceedsFromMaturitiesOfTradingFixedMaturityAndConvertibleFixedMaturityInvestments	119300000	USD
CY2021	wtm	Proceeds From Sale Of Trading Common Equity Securities ProceedsFromSaleOfTradingCommonEquitySecurities	176800000	USD
CY2020	wtm	Proceeds From Sale Of Trading Common Equity Securities ProceedsFromSaleOfTradingCommonEquitySecurities	787900000	USD
CY2019	wtm	Proceeds From Sale Of Trading Common Equity Securities ProceedsFromSaleOfTradingCommonEquitySecurities	467200000	USD
CY2021	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	106400000	USD
CY2020	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	69900000	USD
CY2019	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	29400000	USD
CY2021	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	218000000.0	USD
CY2020	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	76800000	USD
CY2019	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	177700000	USD
CY2021	wtm	Payments To Acquire Trading Common Equity Securities PaymentsToAcquireTradingCommonEquitySecurities	203400000	USD
CY2020	wtm	Payments To Acquire Trading Common Equity Securities PaymentsToAcquireTradingCommonEquitySecurities	33800000	USD
CY2019	wtm	Payments To Acquire Trading Common Equity Securities PaymentsToAcquireTradingCommonEquitySecurities	29800000	USD
CY2021	wtm	Payments To Acquire Trading Fixed Maturity And Convertible Fixed Maturity Investments PaymentsToAcquireTradingFixedMaturityAndConvertibleFixedMaturityInvestments	1216700000	USD
CY2020	wtm	Payments To Acquire Trading Fixed Maturity And Convertible Fixed Maturity Investments PaymentsToAcquireTradingFixedMaturityAndConvertibleFixedMaturityInvestments	537700000	USD
CY2019	wtm	Payments To Acquire Trading Fixed Maturity And Convertible Fixed Maturity Investments PaymentsToAcquireTradingFixedMaturityAndConvertibleFixedMaturityInvestments	539200000	USD
CY2021	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	52200000	USD
CY2020	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	13400000	USD
CY2019	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	12800000	USD
CY2021	wtm	Restricted Cash Acquired From Acquisition RestrictedCashAcquiredFromAcquisition	0.0	USD
CY2020	wtm	Restricted Cash Acquired From Acquisition RestrictedCashAcquiredFromAcquisition	8400000	USD
CY2019	wtm	Restricted Cash Acquired From Acquisition RestrictedCashAcquiredFromAcquisition	0.0	USD
CY2021	us-gaap	Payments To Acquire Businesses And Interest In Affiliates PaymentsToAcquireBusinessesAndInterestInAffiliates	39100000	USD
CY2020	us-gaap	Payments To Acquire Businesses And Interest In Affiliates PaymentsToAcquireBusinessesAndInterestInAffiliates	127300000	USD
CY2019	us-gaap	Payments To Acquire Businesses And Interest In Affiliates PaymentsToAcquireBusinessesAndInterestInAffiliates	258000000.0	USD
CY2021	wtm	Proceeds From Release Of Cash Placed In Escrow ProceedsFromReleaseOfCashPlacedInEscrow	646300000	USD
CY2020	wtm	Proceeds From Release Of Cash Placed In Escrow ProceedsFromReleaseOfCashPlacedInEscrow	-646300000	USD
CY2019	wtm	Proceeds From Release Of Cash Placed In Escrow ProceedsFromReleaseOfCashPlacedInEscrow	0	USD
CY2021	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-2500000	USD
CY2020	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	400000	USD
CY2019	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	27300000	USD
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-208300000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	64600000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-59900000	USD
CY2021	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	436700000	USD
CY2020	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	84600000	USD
CY2019	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	206400000	USD
CY2021	us-gaap	Repayments Of Debt RepaymentsOfDebt	154700000	USD
CY2020	us-gaap	Repayments Of Debt RepaymentsOfDebt	4500000	USD
CY2019	us-gaap	Repayments Of Debt RepaymentsOfDebt	22900000	USD
CY2021	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	3100000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	3200000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	3200000	USD
CY2021	wtm	Acquisitions Of Subsidiary Shares From Non Controlling Interest Shareholders AcquisitionsOfSubsidiarySharesFromNonControllingInterestShareholders	-6500000	USD
CY2020	wtm	Acquisitions Of Subsidiary Shares From Non Controlling Interest Shareholders AcquisitionsOfSubsidiarySharesFromNonControllingInterestShareholders	0	USD
CY2019	wtm	Acquisitions Of Subsidiary Shares From Non Controlling Interest Shareholders AcquisitionsOfSubsidiarySharesFromNonControllingInterestShareholders	0	USD
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	100100000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	78500000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0	USD
CY2021	wtm	Repurchaseof Shares From Noncontrolling Interest Shareholders RepurchaseofSharesFromNoncontrollingInterestShareholders	400000	USD
CY2020	wtm	Repurchaseof Shares From Noncontrolling Interest Shareholders RepurchaseofSharesFromNoncontrollingInterestShareholders	500000	USD
CY2019	wtm	Repurchaseof Shares From Noncontrolling Interest Shareholders RepurchaseofSharesFromNoncontrollingInterestShareholders	21100000	USD
CY2019	wtm	Proceeds From Issuanceof Sharesto Noncontrolling Interest Shareholders ProceedsFromIssuanceofSharestoNoncontrollingInterestShareholders	62700000	USD
CY2021	wtm	Proceeds From Issuanceof Sharesto Noncontrolling Interest Shareholders ProceedsFromIssuanceofSharestoNoncontrollingInterestShareholders	0	USD
CY2020	wtm	Proceeds From Issuanceof Sharesto Noncontrolling Interest Shareholders ProceedsFromIssuanceofSharestoNoncontrollingInterestShareholders	0	USD
CY2019	wtm	Members Capital Contribution MembersCapitalContribution	54600000	USD
CY2021	us-gaap	Proceeds From Payments To Minority Shareholders ProceedsFromPaymentsToMinorityShareholders	1500000	USD
CY2020	us-gaap	Proceeds From Payments To Minority Shareholders ProceedsFromPaymentsToMinorityShareholders	1700000	USD
CY2019	us-gaap	Proceeds From Payments To Minority Shareholders ProceedsFromPaymentsToMinorityShareholders	-26200000	USD
CY2021	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	0	USD
CY2020	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	7000000.0	USD
CY2019	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	7600000	USD
CY2021	wtm	Members Capital Contribution MembersCapitalContribution	62200000	USD
CY2020	wtm	Members Capital Contribution MembersCapitalContribution	68900000	USD
CY2021	wtm	Fidus Re Premium Payment FidusRePremiumPayment	8800000	USD
CY2020	wtm	Fidus Re Premium Payment FidusRePremiumPayment	3000000.0	USD
CY2019	wtm	Fidus Re Premium Payment FidusRePremiumPayment	3000000.0	USD
CY2021	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-22200000	USD
CY2020	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-9500000	USD
CY2019	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-9200000	USD
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	217600000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	49000000.0	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	230500000	USD
CY2021	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	200000	USD
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-2800000	USD
CY2019	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	600000	USD
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	48100000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	50200000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	50700000	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	78400000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	56300000	USD
CY2018Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	50000000.0	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	211200000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	161000000.0	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	110300000	USD
CY2021Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	93700000	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	78400000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	56300000	USD
CY2021Q4	us-gaap	Disposal Group Including Discontinued Operation Cash And Cash Equivalents DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents	700000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Cash And Cash Equivalents DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents	0.0	USD
CY2019Q4	us-gaap	Disposal Group Including Discontinued Operation Cash And Cash Equivalents DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents	0.0	USD
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	259300000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	211200000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	161000000.0	USD
CY2021	us-gaap	Use Of Estimates UseOfEstimates	<div><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="text-indent:18pt"><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 in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.</span></div>
CY2021	wtm	Percentage Of Investments Recorded At Fair Value PercentageOfInvestmentsRecordedAtFairValue	0.68
CY2021	wtm	Fair Value Measurements Variance Thresholdfor Outliers FairValueMeasurementsVarianceThresholdforOutliers	500000	USD
CY2021	wtm	Fair Value Measurements Variance Thresholdfor Outliers Percent FairValueMeasurementsVarianceThresholdforOutliersPercent	0.05
CY2021Q4	us-gaap	Other Long Term Investments OtherLongTermInvestments	1400000000	USD
CY2021Q4	us-gaap	Accumulated Other Comprehensive Income Loss Foreign Currency Translation Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax	5100000	USD
CY2021	us-gaap	Derivatives Reporting Of Derivative Activity DerivativesReportingOfDerivativeActivity	<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Derivatives </span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">From time to time, White Mountains holds derivative financial instruments for risk management purposes. White Mountains recognizes all derivatives as either assets or liabilities, measured at fair value, on its consolidated balance sheet. Changes in the fair value of derivative instruments that meet the criteria for hedge accounting are recognized in other comprehensive income (loss) and reclassified into current period pre-tax income (loss) when the hedged items are recognized therein. Changes in the fair value of derivative instruments that do not meet the criteria for hedge accounting are recognized in current period pre-tax income (loss).</span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of December 31, 2021 and 2020, White Mountains holds interest rate cap derivative instruments that do not meet the criteria for hedge accounting. As of December 31, 2021 and 2020, White Mountains holds an interest rate swap derivative instrument that meets the criteria for hedge accounting. See </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Note 9 — “Derivatives”</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">.</span></div>
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Foreign Currency Translation Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax	5600000	USD
CY2018Q4	wtm	Business Combination Recognized Identifiable Assets Acquiredand Liabilities Assumed Goodwilland Intangible Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedGoodwillandIntangibleAssets	59400000	USD
CY2021	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	84800000	USD
CY2020	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	6200000	USD
CY2020	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	132200000	USD
CY2019	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	81000000.0	USD
CY2021	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	2300000	USD
CY2020	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	1200000	USD
CY2019	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	1300000	USD
CY2021	us-gaap	Net Investment Income NetInvestmentIncome	82500000	USD
CY2020	us-gaap	Net Investment Income NetInvestmentIncome	131000000.0	USD
CY2019	us-gaap	Net Investment Income NetInvestmentIncome	79700000	USD
CY2021	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	156800000	USD
CY2020	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	187100000	USD
CY2019	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	96600000	USD
CY2021	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	-395200000	USD
CY2020	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	529700000	USD
CY2019	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	336600000	USD
CY2021	wtm	Gain Loss On Investments Exchange Rate Effect GainLossOnInvestmentsExchangeRateEffect	-7700000	USD
CY2020	us-gaap	Debt Securities Trading Realized Loss DebtSecuritiesTradingRealizedLoss	27300000	USD
CY2020	wtm	Gain Loss On Investments Exchange Rate Effect GainLossOnInvestmentsExchangeRateEffect	4000000.0	USD
CY2019	wtm	Gain Loss On Investments Exchange Rate Effect GainLossOnInvestmentsExchangeRateEffect	-300000	USD
CY2021	us-gaap	Debt Securities Trading Realized Gain DebtSecuritiesTradingRealizedGain	212300000	USD
CY2020	us-gaap	Debt Securities Trading Realized Gain DebtSecuritiesTradingRealizedGain	214400000	USD
CY2019	us-gaap	Debt Securities Trading Realized Gain DebtSecuritiesTradingRealizedGain	104000000	USD
CY2021	us-gaap	Debt Securities Trading Realized Loss DebtSecuritiesTradingRealizedLoss	55500000	USD
CY2019	us-gaap	Debt Securities Trading Realized Loss DebtSecuritiesTradingRealizedLoss	7400000	USD
CY2021	us-gaap	Proceeds From Sale Maturity And Collection Of Longterm Investments ProceedsFromSaleMaturityAndCollectionOfLongtermInvestments	800000000	USD
CY2020	us-gaap	Proceeds From Sale Maturity And Collection Of Longterm Investments ProceedsFromSaleMaturityAndCollectionOfLongtermInvestments	1400000000	USD
CY2019	us-gaap	Proceeds From Sale Maturity And Collection Of Longterm Investments ProceedsFromSaleMaturityAndCollectionOfLongtermInvestments	1000000000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	1895500000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	1908900000	USD
CY2021	wtm	Percentage Of Investments Recorded At Fair Value PercentageOfInvestmentsRecordedAtFairValue	0.68
CY2020	wtm	Percentage Of Investments Recorded At Fair Value PercentageOfInvestmentsRecordedAtFairValue	0.73
CY2021Q4	wtm	Investments Held In Trusts InvestmentsHeldInTrusts	479500000	USD
CY2020Q4	wtm	Investments Held In Trusts InvestmentsHeldInTrusts	432400000	USD
CY2021Q4	us-gaap	Assets Held By Insurance Regulators AssetsHeldByInsuranceRegulators	4800000	USD
CY2020Q4	us-gaap	Assets Held By Insurance Regulators AssetsHeldByInsuranceRegulators	11900000	USD
CY2021Q4	us-gaap	Other Long Term Investments OtherLongTermInvestments	1377800000	USD
CY2020Q4	us-gaap	Other Long Term Investments OtherLongTermInvestments	786800000	USD
CY2021Q4	us-gaap	Goodwill Fair Value Disclosure GoodwillFairValueDisclosure	675700000	USD
CY2021	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	30200000	USD
CY2021Q4	us-gaap	Goodwill Goodwill	645500000	USD
CY2020Q4	us-gaap	Goodwill Fair Value Disclosure GoodwillFairValueDisclosure	525500000	USD
CY2020	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2020Q4	us-gaap	Goodwill Goodwill	525500000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Fair Value Disclosure FiniteLivedIntangibleAssetsFairValueDisclosure	1196100000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	93800000	USD
CY2021	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	36400000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Fair Value Disclosure FiniteLivedIntangibleAssetsFairValueDisclosure	843300000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	54700000	USD
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	39800000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	28300000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	21800000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	39400000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	36000000.0	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	32700000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	30500000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	106100000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	244700000	USD
CY2021Q4	us-gaap	Indefinite Lived Intangible Assets Excluding Goodwill IndefiniteLivedIntangibleAssetsExcludingGoodwill	175700000	USD
CY2021	us-gaap	Schedule Of Liability For Unpaid Claims And Claims Adjustment Expense ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense	The following table summarizes the loss and LAE reserve activity of Ark’s insurance and reinsurance subsidiaries for the year ended December 31, 2021:<div style="text-align:center"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:87.134%"><tr><td style="width:1.0%"/><td style="width:82.121%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.638%"/><td style="width:0.1%"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td style="width:1.0%"/><td style="width:14.841%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="border-top:1pt solid #000;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:700;line-height:100%">Millions</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="border-top:1pt solid #000;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%">Year Ended <br/>December 31, 2021</span></td></tr><tr><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Gross beginning balance</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td style="border-top:1pt solid #000;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:700;line-height:100%">$</span></td><td style="border-top:1pt solid #000;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:700;line-height:100%">696.0</span><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-top:1pt solid #000;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:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Less: beginning reinsurance recoverable on unpaid losses </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.2pt;font-weight:400;line-height:100%;position:relative;top:-2.8pt;vertical-align:baseline">(1)</span></div></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><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:700;line-height:100%">(433.4)</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 7pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Net loss and LAE reserves</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="2" style="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:700;line-height:100%">262.6</span><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-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr style="height:8pt"><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="padding:0 1pt"/></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:9pt;font-weight:400;line-height:100%">Losses and LAE incurred relating to:</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="padding:0 1pt"/></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:9pt;font-weight:400;line-height:100%"> Current year losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><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:700;line-height:100%">336.3</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%"> Prior year losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><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:700;line-height:100%">(21.5)</span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Net incurred losses and LAE</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="2" style="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:700;line-height:100%">314.8</span><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-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr style="height:9pt"><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/></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:9pt;font-weight:400;line-height:100%">Loss and LAE paid relating to:</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 13pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Current year losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><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:700;line-height:100%">(43.9)</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 7pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%"> Prior year losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><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:700;line-height:100%">(61.6)</span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Net paid losses and LAE</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="2" style="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:700;line-height:100%">(105.5)</span></td><td style="border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr style="height:9pt"><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Change in TPC Providers’ participation </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.85pt;font-weight:400;line-height:100%;position:relative;top:-3.15pt;vertical-align:baseline">(2)</span></div></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><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:700;line-height:100%">(2.2)</span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Foreign currency translation and other adjustments to loss and LAE reserves</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><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:700;line-height:100%">(3.9)</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr style="height:6pt"><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="padding:0 1pt"/></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:9pt;font-weight:400;line-height:100%">Net ending balance</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><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:700;line-height:100%">465.8</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="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:bottom"><div style="padding-left:6pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Plus: ending reinsurance recoverable on unpaid losses </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.2pt;font-weight:400;line-height:100%;position:relative;top:-2.8pt;vertical-align:baseline">(1)</span></div></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><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:700;line-height:100%">428.9</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="border-bottom:3pt double #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Gross ending balance</span></td><td colspan="3" style="border-bottom:3pt double #000;padding:0 1pt"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td style="border-bottom:3pt double #000;border-top:1pt solid #000;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:700;line-height:100%">$</span></td><td style="border-bottom:3pt double #000;border-top:1pt solid #000;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:700;line-height:100%">894.7</span><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 #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-top:3pt;padding-left:40.5pt;padding-right:31.5pt;text-indent:-9pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.2pt;font-weight:400;line-height:120%;position:relative;top:-2.8pt;vertical-align:baseline">(1)</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"> The beginning reinsurance recoverable on unpaid losses and ending reinsurance recoverable on unpaid losses includes amounts attributable to TPC Providers of $319.2 and $276.8.</span></div><div style="padding-left:40.5pt;padding-right:31.5pt;text-indent:-9pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.2pt;font-weight:400;line-height:112%;position:relative;top:-2.8pt;vertical-align:baseline">(2)</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:112%"> Amount represents a decrease in net loss and LAE reserves due to a change in the TPC Providers’ participation during 2021, related to the RITC for the 2018 year of account.</span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:112%">The following table summarizes the unpaid loss and LAE reserves, net of reinsurance recoverables on unpaid losses, for each of Ark’s major reserving lines of business as of December 31, 2021:</span></div><div style="text-indent:18pt"><span><br/></span></div><div style="text-indent:18pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:96.491%"><tr><td style="width:1.0%"/><td style="width:83.748%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.557%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:13.295%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"><br/><br/></span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Millions</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%">As of<br/>December 31, 2021</span></td></tr><tr><td colspan="3" style="border-top:1pt solid #000;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%">Property and Accident & Health</span></td><td colspan="3" style="padding:0 1pt"/><td style="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-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%">175.0 </span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Marine & Energy</span></td><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%">99.3 </span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Specialty</span></td><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%">85.2 </span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Casualty - Active </span></td><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%">37.4 </span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Casualty - Runoff</span></td><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%">68.4 </span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:112%">Other</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding: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%">0.5</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:10pt;font-weight:400;line-height:112%"> Unpaid loss and LAE reserves, net of reinsurance recoverables on unpaid losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="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%">465.8 </span></td><td style="border-top:1pt solid #000;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:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Plus: Reinsurance recoverables on unpaid losses </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:6.5pt;font-weight:400;line-height:100%;position:relative;top:-3.5pt;vertical-align:baseline">(1)</span></div></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/></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:10pt;font-weight:400;line-height:100%">Property and Accident & Health</span></td><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%">145.2 </span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Marine & Energy</span></td><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%">70.2 </span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Specialty</span></td><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%">68.9 </span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Casualty - Active</span></td><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%">41.4 </span></td><td style="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:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Casualty - Runoff</span></td><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%">103.2 </span></td><td style="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:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:112%"> Total Reinsurance recoverables on unpaid losses </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:6.5pt;font-weight:400;line-height:112%;position:relative;top:-3.5pt;vertical-align:baseline">(1)</span></div></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="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%">428.9 </span></td><td style="border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="border-bottom:3pt double #000000;padding:2px 1pt 2px 13pt;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 unpaid loss and LAE reserves</span></td><td colspan="3" style="border-bottom:3pt double #000000;padding:0 1pt"/><td style="border-bottom:3pt double #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:700;line-height:100%">$</span></td><td style="border-bottom:3pt double #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:700;line-height:100%">894.7</span><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;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="padding-left:9pt;text-indent:9pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.2pt;font-weight:400;line-height:120%;position:relative;top:-2.8pt;vertical-align:baseline">(1)</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"> The reinsurance recoverables on unpaid losses include amounts attributable to TPC Providers of $276.8.</span></div>
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CY2021	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	36500	shares
CY2020	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	40800	shares
CY2019	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	40500	shares
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	3042500	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	3081400	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	3141100	shares
CY2021	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	3079000	shares
CY2020	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	3122200	shares
CY2019	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	3181600	shares
CY2021	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	36500	shares
CY2020	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	40800	shares
CY2019	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	40500	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	3042500	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	3081400	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	3141100	shares
CY2021	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.00
CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.00
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.00
CY2020	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	227.72
CY2019	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	130.02
CY2021	us-gaap	Earnings Per Share Diluted Undistributed EarningsPerShareDilutedUndistributed	-96.53
CY2020	us-gaap	Earnings Per Share Diluted Undistributed EarningsPerShareDilutedUndistributed	226.72
CY2019	us-gaap	Earnings Per Share Diluted Undistributed EarningsPerShareDilutedUndistributed	129.02
CY2021	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	-95.53
CY2021	wtm	Income Loss From Continuing Operatings Excluding Portion Attributable To Noncontrolling Interest Net IncomeLossFromContinuingOperatingsExcludingPortionAttributableToNoncontrollingInterestNet	-290600000	USD
CY2020	wtm	Income Loss From Continuing Operatings Excluding Portion Attributable To Noncontrolling Interest Net IncomeLossFromContinuingOperatingsExcludingPortionAttributableToNoncontrollingInterestNet	701700000	USD
CY2019	wtm	Income Loss From Continuing Operatings Excluding Portion Attributable To Noncontrolling Interest Net IncomeLossFromContinuingOperatingsExcludingPortionAttributableToNoncontrollingInterestNet	408400000	USD
CY2021	wtm	Dividends Common Stock Cash Net Of Restricted Common Share Amounts DividendsCommonStockCashNetOfRestrictedCommonShareAmounts	3100000	USD
CY2020	wtm	Dividends Common Stock Cash Net Of Restricted Common Share Amounts DividendsCommonStockCashNetOfRestrictedCommonShareAmounts	3100000	USD
CY2019	wtm	Dividends Common Stock Cash Net Of Restricted Common Share Amounts DividendsCommonStockCashNetOfRestrictedCommonShareAmounts	3200000	USD
CY2019	us-gaap	Undistributed Earnings UndistributedEarnings	405200000	USD
CY2021	us-gaap	Undistributed Earnings UndistributedEarnings	-293700000	USD
CY2020	us-gaap	Undistributed Earnings UndistributedEarnings	698600000	USD
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	42200000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	37600000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	45200000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	38300000	USD
CY2021	us-gaap	Operating Lease Cost OperatingLeaseCost	9900000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	7700000	USD
CY2021	us-gaap	Sublease Income SubleaseIncome	400000	USD
CY2020	us-gaap	Sublease Income SubleaseIncome	400000	USD
CY2021	us-gaap	Lease Cost LeaseCost	9500000	USD
CY2020	us-gaap	Lease Cost LeaseCost	7300000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	10900000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	9900000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	8500000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	6800000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	4300000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	11900000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	52300000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	7100000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	45200000	USD
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	42200000	USD
CY2021Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.05
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	45200000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	37600000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.046
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	38300000	USD
CY2021	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	107500000	USD
CY2021	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	1091
CY2020	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	85100000	USD
CY2020	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	859
CY2019	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	4900000	USD
CY2019	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	858
CY2021	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	15066	shares
CY2020	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	15745	shares
CY2019	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	17917	shares
CY2021	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	3100000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	3200000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	3200000	USD
CY2021	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.00
CY2021Q4	us-gaap	Minority Interest MinorityInterest	156600000	USD
CY2020Q4	us-gaap	Minority Interest MinorityInterest	-88100000	USD
CY2021Q4	wtm	Collateral Trusts Investments And Cash CollateralTrustsInvestmentsAndCash	481700000	USD
CY2021	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	5	segment
CY2021	us-gaap	Premiums Earned Net PremiumsEarnedNet	664200000	USD
CY2021	us-gaap	Net Investment Income NetInvestmentIncome	82500000	USD
CY2021	wtm	Gain Loss On Investments Net Of Tax GainLossOnInvestmentsNetOfTax	134200000	USD
CY2021	wtm	Commission Revenue CommissionRevenue	267600000	USD
CY2021	us-gaap	Other Income OtherIncome	176600000	USD
CY2021	us-gaap	Revenues Revenues	944800000	USD
CY2021	wtm	Insurance Loss And Loss Adjustments Expense InsuranceLossAndLossAdjustmentsExpense	314800000	USD
CY2021	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	186300000	USD
CY2021	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	69300000	USD
CY2021	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	482900000	USD
CY2021	wtm	Broker Commission Expense BrokerCommissionExpense	80200000	USD
CY2021	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	1000000.0	USD
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	39800000	USD
CY2021	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-28700000	USD
CY2021	us-gaap	Interest Expense Debt InterestExpenseDebt	43800000	USD
CY2021	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	1246800000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-302000000.0	USD
CY2020	us-gaap	Premiums Earned Net PremiumsEarnedNet	22800000	USD
CY2020	us-gaap	Net Investment Income NetInvestmentIncome	131000000.0	USD
CY2020	wtm	Gain Loss On Investments Net Of Tax GainLossOnInvestmentsNetOfTax	30800000	USD
CY2020	wtm	Commission Revenue CommissionRevenue	240800000	USD
CY2020	us-gaap	Other Income OtherIncome	69300000	USD
CY2020	us-gaap	Revenues Revenues	1180700000	USD
CY2020	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	7000000.0	USD
CY2020	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	11300000	USD
CY2020	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	387400000	USD
CY2020	wtm	Broker Commission Expense BrokerCommissionExpense	75300000	USD
CY2020	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	-3300000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	28300000	USD
CY2020	us-gaap	Interest Expense Debt InterestExpenseDebt	29500000	USD
CY2020	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	535500000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	645200000	USD
CY2019	us-gaap	Premiums Earned Net PremiumsEarnedNet	16300000	USD
CY2019	wtm	Gain Loss On Investments Net Of Tax GainLossOnInvestmentsNetOfTax	253200000	USD
CY2019	wtm	Realized Gain From Transaction RealizedGainFromTransaction	67500000	USD
CY2019	us-gaap	Net Investment Income NetInvestmentIncome	79700000	USD
CY2019	wtm	Commission Revenue CommissionRevenue	249100000	USD
CY2019	us-gaap	Other Income OtherIncome	47600000	USD
CY2019	us-gaap	Revenues Revenues	893400000	USD
CY2019	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	5700000	USD
CY2019	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	48100000	USD
CY2019	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	328200000	USD
CY2019	wtm	Broker Commission Expense BrokerCommissionExpense	64800000	USD
CY2019	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	2100000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	21800000	USD
CY2019	us-gaap	Interest Expense Debt InterestExpenseDebt	17600000	USD
CY2019	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	488300000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	405100000	USD
CY2021Q4	us-gaap	Investments Investments	4265300000	USD
CY2021Q4	us-gaap	Assets Assets	7000700000	USD
CY2021Q4	us-gaap	Liabilities Liabilities	3296000000	USD
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	3548100000	USD
CY2021Q4	us-gaap	Minority Interest MinorityInterest	156600000	USD
CY2020Q4	us-gaap	Investments Investments	2939000000	USD
CY2020Q4	us-gaap	Assets Assets	4831400000	USD
CY2020Q4	us-gaap	Liabilities Liabilities	1013500000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	3906000000	USD
CY2020Q4	us-gaap	Minority Interest MinorityInterest	-88100000	USD
CY2021	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	427500000	USD
CY2021	wtm	Other Revenue OtherRevenue	517300000	USD
CY2021	us-gaap	Revenues Revenues	944800000	USD
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	307900000	USD
CY2020	wtm	Other Revenue OtherRevenue	872800000	USD
CY2020	us-gaap	Revenues Revenues	1180700000	USD
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	294300000	USD
CY2019	wtm	Other Revenue OtherRevenue	599100000	USD
CY2019	us-gaap	Revenues Revenues	893400000	USD
CY2021	us-gaap	Operating Lease Expense OperatingLeaseExpense	9900000	USD
CY2020	us-gaap	Operating Lease Expense OperatingLeaseExpense	7700000	USD
CY2019	us-gaap	Operating Lease Expense OperatingLeaseExpense	7200000	USD
CY2021Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	10900000	USD
CY2021Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	9900000	USD
CY2021Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	8500000	USD
CY2021Q4	wtm	Finance Lease Liability To Be Paid After Year Three FinanceLeaseLiabilityToBePaidAfterYearThree	23000000	USD
CY2021	wtm	Commitments Other Long Term Investments CommitmentsOtherLongTermInvestments	44000000	USD
CY2021	dei	Auditor Name AuditorName	PricewaterhouseCoopers LLP
CY2021	dei	Auditor Location AuditorLocation	Boston, Massachusetts
CY2021Q4	us-gaap	Summary Of Investments Other Than Investments In Related Parties Cost SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCost	3784400000	USD
CY2021Q4	us-gaap	Summary Of Investments Other Than Investments In Related Parties Carrying Amount SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCarryingAmount	4265300000	USD
CY2021Q4	us-gaap	Summary Of Investments Other Than Investments In Related Parties Fair Value SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesFairValue	4265300000	USD
CY2021	wtm	Amortizationof Restricted Sharesand Option Awards AmortizationofRestrictedSharesandOptionAwards	14700000	USD
CY2020	wtm	Amortizationof Restricted Sharesand Option Awards AmortizationofRestrictedSharesandOptionAwards	16600000	USD
CY2019	wtm	Amortizationof Restricted Sharesand Option Awards AmortizationofRestrictedSharesandOptionAwards	10500000	USD
CY2021	wtm	Increase Decrease In Payables From Receivables To Affiliates IncreaseDecreaseInPayablesFromReceivablesToAffiliates	6500000	USD
CY2020	wtm	Increase Decrease In Payables From Receivables To Affiliates IncreaseDecreaseInPayablesFromReceivablesToAffiliates	4800000	USD
CY2019	wtm	Increase Decrease In Payables From Receivables To Affiliates IncreaseDecreaseInPayablesFromReceivablesToAffiliates	6600000	USD

Files In Submission

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$WTM
WHITE MOUNTAINS INSURANCE GROUP LTD Stock $wtm

2021 Q4 Form 10-K Financial Statement

#000077686722000002 Filed on February 28, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTM WHITE MOUNTAINS INSURANCE GROUP LTD Stock $wtm

2021 Q4 Form 10-K Financial Statement

#000077686722000002 Filed on February 28, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTM
WHITE MOUNTAINS INSURANCE GROUP LTD Stock $wtm