$AFG
AMERICAN FINANCIAL GROUP INC Stock $afg

$afg Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-K Financial Statement

#000104204621000011 Filed on February 25, 2021

Income Statement

Concept	2020 Q4	2020	2019 Q4
Revenue	$2.623B	$5.769B	$2.130B
YoY Change	23.15%	-7.15%	26.04%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin		$1.625B
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$51.00M	$615.0M	$64.00M
YoY Change	-20.31%	-14.7%	36.17%
% of Gross Profit
Operating Expenses	$1.715B	$6.973B	$1.853B
YoY Change	-7.45%	-1.25%	8.17%
Operating Profit		$339.0M
YoY Change		-46.53%
Interest Expense	-$24.00M	$88.00M	-$18.00M
YoY Change	33.33%	29.41%	12.5%
% of Operating Profit		25.96%
Other Income/Expense, Net
YoY Change
Pretax Income	$884.0M	$848.0M	$259.0M
YoY Change	241.31%	-23.47%	-764.1%
Income Tax	$190.0M	$25.00M	$68.00M
% Of Pretax Income	21.49%	2.95%	26.25%
Net Earnings	$692.0M	$732.0M	$211.0M
YoY Change	227.96%	-18.39%	-827.59%
Net Earnings / Revenue	26.38%	12.69%	9.91%
Basic Earnings Per Share	$7.99	$8.25	$2.33
Diluted Earnings Per Share	$7.93	$8.20	$2.31
COMMON SHARES
Basic Shares Outstanding	86.60M shares	88.70M shares	90.20M shares
Diluted Shares Outstanding	87.20M shares	89.20M shares	91.30M shares

Balance Sheet

Concept	2020 Q4	2020	2019 Q4
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$1.665B	$1.665B	$2.314B
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets	$678.0M	$678.0M	$975.0M
YoY Change	-30.46%	-30.46%	-10.55%
LONG-TERM ASSETS
Property, Plant & Equipment	$159.0M	$159.0M	$158.0M
YoY Change	0.63%	0.63%
Goodwill	$176.0M		$176.0M
YoY Change	0.0%		0.0%
Intangibles
YoY Change
Long-Term Investments	$1.235B	$16.80B	$1.688B
YoY Change	-26.84%	-70.34%	22.85%
Other Assets	$47.89B	$47.89B
YoY Change
Total Long-Term Assets	$73.03B	$73.03B	$69.16B
YoY Change	5.61%	5.61%	10.89%
TOTAL ASSETS
Total Short-Term Assets	$678.0M	$678.0M	$975.0M
Total Long-Term Assets	$73.03B	$73.03B	$69.16B
Total Assets	$73.71B	$73.71B	$70.13B
YoY Change	5.1%	5.1%	10.52%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$159.0M	$159.0M	$180.0M
YoY Change	-11.67%	-11.67%
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	$159.0M	$159.0M	$180.0M
YoY Change	-11.67%	-11.67%
LONG-TERM LIABILITIES
Long-Term Debt	$1.963B	$1.963B	$1.473B
YoY Change	33.27%	33.27%	13.13%
Other Long-Term Liabilities	$50.80B	$50.80B	$10.42B
YoY Change	387.68%	387.68%	15.66%
Total Long-Term Liabilities	$52.76B	$52.76B	$11.89B
YoY Change	343.77%	343.77%	15.34%
TOTAL LIABILITIES
Total Short-Term Liabilities	$159.0M	$159.0M	$180.0M
Total Long-Term Liabilities	$52.76B	$52.76B	$11.89B
Total Liabilities	$66.92B	$66.92B	$63.86B
YoY Change	4.79%	4.79%	9.19%
SHAREHOLDERS EQUITY
Retained Earnings
YoY Change
Common Stock	$1.367B		$1.397B
YoY Change	-2.15%		4.72%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$6.789B	$6.789B	$6.269B
YoY Change
Total Liabilities & Shareholders Equity	$73.71B	$73.71B	$70.13B
YoY Change	5.1%	5.1%	10.52%

Cashflow Statement

Concept	2020 Q4	2020	2019 Q4
OPERATING ACTIVITIES
Net Income	$692.0M	$732.0M	$211.0M
YoY Change	227.96%	-18.39%	-827.59%
Depreciation, Depletion And Amortization	$51.00M	$615.0M	$64.00M
YoY Change	-20.31%	-14.7%	36.17%
Cash From Operating Activities	$487.0M	$2.183B	$765.0M
YoY Change	-36.34%	-11.12%	-5.09%
INVESTING ACTIVITIES
Capital Expenditures	-$19.00M	-$60.00M	-$11.00M
YoY Change	72.73%	36.36%	-45.0%
Acquisitions
YoY Change
Other Investing Activities	-$773.0M	$1.000M	-$1.276B
YoY Change	-39.42%	-66.67%	-34.73%
Cash From Investing Activities	-$792.0M	-$1.564B	-$1.287B
YoY Change	-38.46%	-48.97%	-34.84%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net		$291.0M
YoY Change		-908.33%
Debt Paid & Issued, Net		$150.0M
YoY Change		0.0%
Cash From Financing Activities	-632.0M	-$123.0M	143.0M
YoY Change	-541.96%	-108.74%	-78.81%
NET CHANGE
Cash From Operating Activities	487.0M	$2.183B	765.0M
Cash From Investing Activities	-792.0M	-$1.564B	-1.287B
Cash From Financing Activities	-632.0M	-$123.0M	143.0M
Net Change In Cash	-937.0M	$496.0M	-379.0M
YoY Change	147.23%	-37.92%	-23.28%
FREE CASH FLOW
Cash From Operating Activities	$487.0M	$2.183B	$765.0M
Capital Expenditures	-$19.00M	-$60.00M	-$11.00M
Free Cash Flow	$506.0M	$2.243B	$776.0M
YoY Change	-34.79%	-10.28%	-6.05%

Facts In Submission

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CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	89900000	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	89000000.0	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	89200000	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	91000000.0	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	90600000	shares
CY2020	us-gaap	Profit Loss ProfitLoss	721000000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	869000000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	517000000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	700000000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	788000000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-544000000	USD
CY2020	afg	Other Comprehensive Income Loss Reclassification Adjustment For Realized Gains Losses Included In Net Income Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentForRealizedGainsLossesIncludedInNetIncomeNetOfTax	307000000	USD
CY2019	afg	Other Comprehensive Income Loss Reclassification Adjustment For Realized Gains Losses Included In Net Income Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentForRealizedGainsLossesIncludedInNetIncomeNetOfTax	9000000	USD
CY2018	afg	Other Comprehensive Income Loss Reclassification Adjustment For Realized Gains Losses Included In Net Income Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentForRealizedGainsLossesIncludedInNetIncomeNetOfTax	-8000000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	393000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	779000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-536000000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	24000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	28000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	2000000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-1000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	7000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-10000000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-1000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	0	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	416000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	815000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-544000000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	1137000000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	1684000000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-27000000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	-9000000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	-28000000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	-13000000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	1146000000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	1712000000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-14000000	USD
CY2017Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5331000000	USD
CY2017Q4	us-gaap	Temporary Equity Carrying Amount Including Portion Attributable To Noncontrolling Interests TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests	3000000	USD
CY2018	us-gaap	Net Income Loss Including Portion Attributable To Nonredeemable Noncontrolling Interest NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest	531000000	USD
CY2018	us-gaap	Net Income Loss Attributable To Redeemable Noncontrolling Interest NetIncomeLossAttributableToRedeemableNoncontrollingInterest	14000000	USD
CY2018	afg	Other Comprehensive Income Loss Net Of Tax Including Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-544000000	USD
CY2018	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	4.45
CY2018	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	397000000	USD
CY2018	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	29000000	USD
CY2018	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2018	us-gaap	Stock Issued During Period Value Share Based Compensation Gross StockIssuedDuringPeriodValueShareBasedCompensationGross	12000000	USD
CY2018	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	3000000	USD
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	23000000	USD
CY2018	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	6000000	USD
CY2018	afg	Stock Repurchased Shares Exchanged In Stock Compensation Plans Value StockRepurchasedSharesExchangedInStockCompensationPlansValue	3000000	USD
CY2018	us-gaap	Stock Issued During Period Value Restricted Stock Award Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures	0	USD
CY2018	us-gaap	Stockholders Equity Other StockholdersEquityOther	11000000	USD
CY2018	us-gaap	Temporary Equity Other Changes TemporaryEquityOtherChanges	11000000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	4972000000	USD
CY2018Q4	us-gaap	Temporary Equity Carrying Amount Including Portion Attributable To Noncontrolling Interests TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests	0	USD
CY2019	us-gaap	Net Income Loss Including Portion Attributable To Nonredeemable Noncontrolling Interest NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest	895000000	USD
CY2019	us-gaap	Net Income Loss Attributable To Redeemable Noncontrolling Interest NetIncomeLossAttributableToRedeemableNoncontrollingInterest	26000000	USD
CY2019	afg	Other Comprehensive Income Loss Net Of Tax Including Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	815000000	USD
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	4.95
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	446000000	USD
CY2019	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	31000000	USD
CY2019	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation Gross StockIssuedDuringPeriodValueShareBasedCompensationGross	8000000	USD
CY2019	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	2000000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	23000000	USD
CY2019	afg	Stock Repurchased Shares Exchanged In Stock Compensation Plans Value StockRepurchasedSharesExchangedInStockCompensationPlansValue	5000000	USD
CY2019	us-gaap	Stock Issued During Period Value Restricted Stock Award Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures	0	USD
CY2019	us-gaap	Stockholders Equity Other StockholdersEquityOther	26000000	USD
CY2019	us-gaap	Temporary Equity Other Changes TemporaryEquityOtherChanges	26000000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	6269000000	USD
CY2019Q4	us-gaap	Temporary Equity Carrying Amount Including Portion Attributable To Noncontrolling Interests TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests	0	USD
CY2020	us-gaap	Net Income Loss Including Portion Attributable To Nonredeemable Noncontrolling Interest NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest	734000000	USD
CY2020	us-gaap	Net Income Loss Attributable To Redeemable Noncontrolling Interest NetIncomeLossAttributableToRedeemableNoncontrollingInterest	13000000	USD
CY2020	afg	Other Comprehensive Income Loss Net Of Tax Including Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	414000000	USD
CY2020	afg	Other Comprehensive Income Loss Net Of Tax Attributable To Redeemable Noncontrolling Interests OtherComprehensiveIncomeLossNetOfTaxAttributableToRedeemableNoncontrollingInterests	2000000	USD
CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	3.85
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	336000000	USD
CY2020	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	14000000	USD
CY2020	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2020	us-gaap	Stock Issued During Period Value Share Based Compensation Gross StockIssuedDuringPeriodValueShareBasedCompensationGross	10000000	USD
CY2020	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	2000000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	20000000	USD
CY2020	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	313000000	USD
CY2020	afg	Stock Repurchased Shares Exchanged In Stock Compensation Plans Value StockRepurchasedSharesExchangedInStockCompensationPlansValue	11000000	USD
CY2020	us-gaap	Stock Issued During Period Value Restricted Stock Award Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures	0	USD
CY2020	us-gaap	Stockholders Equity Other StockholdersEquityOther	21000000	USD
CY2020	us-gaap	Temporary Equity Other Changes TemporaryEquityOtherChanges	11000000	USD
CY2020Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	6789000000	USD
CY2020Q4	us-gaap	Temporary Equity Carrying Amount Including Portion Attributable To Noncontrolling Interests TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests	0	USD
CY2020	us-gaap	Profit Loss ProfitLoss	721000000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	869000000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	517000000	USD
CY2020	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	299000000	USD
CY2019	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	259000000	USD
CY2018	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	210000000	USD
CY2020	afg	Annuity Benefits AnnuityBenefits	1192000000	USD
CY2019	afg	Annuity Benefits AnnuityBenefits	1151000000	USD
CY2018	afg	Annuity Benefits AnnuityBenefits	998000000	USD
CY2020	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	313000000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	2083000000	USD
CY2019	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	288000000	USD
CY2018	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	-265000000	USD
CY2020	us-gaap	Proceeds From Payments For Trading Securities ProceedsFromPaymentsForTradingSecurities	20000000	USD
CY2019	us-gaap	Proceeds From Payments For Trading Securities ProceedsFromPaymentsForTradingSecurities	-5000000	USD
CY2018	us-gaap	Proceeds From Payments For Trading Securities ProceedsFromPaymentsForTradingSecurities	111000000	USD
CY2020	afg	Deferred Annuity And Life Policy Acquisition Costs DeferredAnnuityAndLifePolicyAcquisitionCosts	154000000	USD
CY2019	afg	Deferred Annuity And Life Policy Acquisition Costs DeferredAnnuityAndLifePolicyAcquisitionCosts	206000000	USD
CY2018	afg	Deferred Annuity And Life Policy Acquisition Costs DeferredAnnuityAndLifePolicyAcquisitionCosts	263000000	USD
CY2020	afg	Increase Decreasein Reinsuranceand Other Receivables IncreaseDecreaseinReinsuranceandOtherReceivables	533000000	USD
CY2019	afg	Increase Decreasein Reinsuranceand Other Receivables IncreaseDecreaseinReinsuranceandOtherReceivables	112000000	USD
CY2018	afg	Increase Decreasein Reinsuranceand Other Receivables IncreaseDecreaseinReinsuranceandOtherReceivables	211000000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-138000000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	406000000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-96000000	USD
CY2020	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	812000000	USD
CY2019	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	703000000	USD
CY2018	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	425000000	USD
CY2020	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	13000000	USD
CY2019	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	62000000	USD
CY2018	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	9000000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-71000000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	516000000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-140000000	USD
CY2020	afg	Changein Managed Investment Entities Assets And Liabilities ChangeinManagedInvestmentEntitiesAssetsAndLiabilities	-25000000	USD
CY2019	afg	Changein Managed Investment Entities Assets And Liabilities ChangeinManagedInvestmentEntitiesAssetsAndLiabilities	-23000000	USD
CY2018	afg	Changein Managed Investment Entities Assets And Liabilities ChangeinManagedInvestmentEntitiesAssetsAndLiabilities	-148000000	USD
CY2020	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	34000000	USD
CY2019	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	-110000000	USD
CY2018	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	-82000000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	2183000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	2456000000	USD
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	10335000000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	8260000000	USD
CY2018	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	10183000000	USD
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Equity PaymentsToAcquireAvailableForSaleSecuritiesEquity	404000000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Equity PaymentsToAcquireAvailableForSaleSecuritiesEquity	242000000	USD
CY2018	us-gaap	Payments To Acquire Available For Sale Securities Equity PaymentsToAcquireAvailableForSaleSecuritiesEquity	568000000	USD
CY2020	us-gaap	Payments To Acquire Mortgage Notes Receivable PaymentsToAcquireMortgageNotesReceivable	372000000	USD
CY2019	us-gaap	Payments To Acquire Mortgage Notes Receivable PaymentsToAcquireMortgageNotesReceivable	442000000	USD
CY2018	us-gaap	Payments To Acquire Mortgage Notes Receivable PaymentsToAcquireMortgageNotesReceivable	167000000	USD
CY2020	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	897000000	USD
CY2019	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	991000000	USD
CY2018	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	973000000	USD
CY2020	afg	Purchases Of Real Estate Property And Equipment PurchasesOfRealEstatePropertyAndEquipment	60000000	USD
CY2019	afg	Purchases Of Real Estate Property And Equipment PurchasesOfRealEstatePropertyAndEquipment	44000000	USD
CY2018	afg	Purchases Of Real Estate Property And Equipment PurchasesOfRealEstatePropertyAndEquipment	80000000	USD
CY2020	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	3000000	USD
CY2019	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	0	USD
CY2018	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	36000000	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	5749000000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	4567000000	USD
CY2018	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	4948000000	USD
CY2020	us-gaap	Proceeds From Sale And Collection Of Mortgage Notes Receivable ProceedsFromSaleAndCollectionOfMortgageNotesReceivable	84000000	USD
CY2019	us-gaap	Proceeds From Sale And Collection Of Mortgage Notes Receivable ProceedsFromSaleAndCollectionOfMortgageNotesReceivable	184000000	USD
CY2018	us-gaap	Proceeds From Sale And Collection Of Mortgage Notes Receivable ProceedsFromSaleAndCollectionOfMortgageNotesReceivable	201000000	USD
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	3729000000	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	927000000	USD
CY2018	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	501000000	USD
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Equity ProceedsFromSaleOfAvailableForSaleSecuritiesEquity	656000000	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities Equity ProceedsFromSaleOfAvailableForSaleSecuritiesEquity	453000000	USD
CY2018	us-gaap	Proceeds From Sale Of Available For Sale Securities Equity ProceedsFromSaleOfAvailableForSaleSecuritiesEquity	247000000	USD
CY2020	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	988000000	USD
CY2019	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	771000000	USD
CY2018	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	883000000	USD
CY2020	afg	Proceeds From Sales Of Real Estate Property And Equipment ProceedsFromSalesOfRealEstatePropertyAndEquipment	5000000	USD
CY2019	afg	Proceeds From Sales Of Real Estate Property And Equipment ProceedsFromSalesOfRealEstatePropertyAndEquipment	4000000	USD
CY2018	afg	Proceeds From Sales Of Real Estate Property And Equipment ProceedsFromSalesOfRealEstatePropertyAndEquipment	3000000	USD
CY2020	us-gaap	Proceeds From Divestiture Of Interest In Consolidated Subsidiaries ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries	3000000	USD
CY2019	us-gaap	Proceeds From Divestiture Of Interest In Consolidated Subsidiaries ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries	0	USD
CY2018	us-gaap	Proceeds From Divestiture Of Interest In Consolidated Subsidiaries ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries	0	USD
CY2020	afg	Net Change In Cash And Cash Equivalents From The Acquisition Or Disposition Of Businesses NetChangeInCashAndCashEquivalentsFromTheAcquisitionOrDispositionOfBusinesses	-425000000	USD
CY2019	afg	Net Change In Cash And Cash Equivalents From The Acquisition Or Disposition Of Businesses NetChangeInCashAndCashEquivalentsFromTheAcquisitionOrDispositionOfBusinesses	0	USD
CY2018	afg	Net Change In Cash And Cash Equivalents From The Acquisition Or Disposition Of Businesses NetChangeInCashAndCashEquivalentsFromTheAcquisitionOrDispositionOfBusinesses	13000000	USD
CY2020	afg	Purchases Of Investments By Managed Investment Entities PurchasesOfInvestmentsByManagedInvestmentEntities	1502000000	USD
CY2019	afg	Purchases Of Investments By Managed Investment Entities PurchasesOfInvestmentsByManagedInvestmentEntities	1398000000	USD
CY2018	afg	Purchases Of Investments By Managed Investment Entities PurchasesOfInvestmentsByManagedInvestmentEntities	2117000000	USD
CY2020	afg	Proceeds From Sales And Redemptions Of Investments By Managed Investment Entities ProceedsFromSalesAndRedemptionsOfInvestmentsByManagedInvestmentEntities	1221000000	USD
CY2019	afg	Proceeds From Sales And Redemptions Of Investments By Managed Investment Entities ProceedsFromSalesAndRedemptionsOfInvestmentsByManagedInvestmentEntities	1409000000	USD
CY2018	afg	Proceeds From Sales And Redemptions Of Investments By Managed Investment Entities ProceedsFromSalesAndRedemptionsOfInvestmentsByManagedInvestmentEntities	1948000000	USD
CY2020	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	1000000	USD
CY2019	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	3000000	USD
CY2018	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-30000000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1564000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-3065000000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-5350000000	USD
CY2020	us-gaap	Proceeds From Annuities And Investment Certificates ProceedsFromAnnuitiesAndInvestmentCertificates	4287000000	USD
CY2019	us-gaap	Proceeds From Annuities And Investment Certificates ProceedsFromAnnuitiesAndInvestmentCertificates	4960000000	USD
CY2018	us-gaap	Proceeds From Annuities And Investment Certificates ProceedsFromAnnuitiesAndInvestmentCertificates	5632000000	USD
CY2020	afg	Annuity Receipts Ceded AnnuityReceiptsCeded	492000000	USD
CY2019	afg	Annuity Receipts Ceded AnnuityReceiptsCeded	0	USD
CY2018	afg	Annuity Receipts Ceded AnnuityReceiptsCeded	0	USD
CY2020	us-gaap	Repayments Of Annuities And Investment Certificates RepaymentsOfAnnuitiesAndInvestmentCertificates	3711000000	USD
CY2019	us-gaap	Repayments Of Annuities And Investment Certificates RepaymentsOfAnnuitiesAndInvestmentCertificates	3358000000	USD
CY2018	us-gaap	Repayments Of Annuities And Investment Certificates RepaymentsOfAnnuitiesAndInvestmentCertificates	2916000000	USD
CY2020	afg	Ceded Annuity Surrenders Benefits And Withdrawals CededAnnuitySurrendersBenefitsAndWithdrawals	206000000	USD
CY2019	afg	Ceded Annuity Surrenders Benefits And Withdrawals CededAnnuitySurrendersBenefitsAndWithdrawals	0	USD
CY2018	afg	Ceded Annuity Surrenders Benefits And Withdrawals CededAnnuitySurrendersBenefitsAndWithdrawals	0	USD
CY2020	afg	Net Transfers From To Separate Accounts NetTransfersFromToSeparateAccounts	61000000	USD
CY2019	afg	Net Transfers From To Separate Accounts NetTransfersFromToSeparateAccounts	60000000	USD
CY2018	afg	Net Transfers From To Separate Accounts NetTransfersFromToSeparateAccounts	47000000	USD
CY2020	afg	Cash Transferred To Annuity Reinsurer CashTransferredToAnnuityReinsurer	554000000	USD
CY2019	afg	Cash Transferred To Annuity Reinsurer CashTransferredToAnnuityReinsurer	0	USD
CY2018	afg	Cash Transferred To Annuity Reinsurer CashTransferredToAnnuityReinsurer	0	USD
CY2020	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	634000000	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	315000000	USD
CY2018	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
CY2020	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	150000000	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	150000000	USD
CY2018	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
CY2020	afg	Proceeds From Issuance Of Managed Investment Entities ProceedsFromIssuanceOfManagedInvestmentEntities	429000000	USD
CY2019	afg	Proceeds From Issuance Of Managed Investment Entities ProceedsFromIssuanceOfManagedInvestmentEntities	371000000	USD
CY2018	afg	Proceeds From Issuance Of Managed Investment Entities ProceedsFromIssuanceOfManagedInvestmentEntities	1983000000	USD
CY2020	afg	Retirement Of Managed Investment Entities Liabilities RetirementOfManagedInvestmentEntitiesLiabilities	208000000	USD
CY2019	afg	Retirement Of Managed Investment Entities Liabilities RetirementOfManagedInvestmentEntitiesLiabilities	382000000	USD
CY2018	afg	Retirement Of Managed Investment Entities Liabilities RetirementOfManagedInvestmentEntitiesLiabilities	1935000000	USD
CY2020	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	22000000	USD
CY2019	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	36000000	USD
CY2018	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	33000000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	313000000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0	USD
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	6000000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	334000000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	444000000	USD
CY2018	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	394000000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-123000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	1408000000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	2444000000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	496000000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	799000000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-823000000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	2314000000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1515000000	USD
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	2338000000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	2810000000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	2314000000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1515000000	USD
CY2020	us-gaap	Basis Of Accounting BasisOfAccounting	<div><span style="color:#003366;font-family:'Arial',sans-serif;font-size:11pt;font-weight:700;line-height:120%">Basis of Presentation</span><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:700;line-height:120%"> </span><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:400;line-height:120%">The consolidated financial statements include the accounts of American Financial Group, Inc. and its subsidiaries (“AFG”). Certain reclassifications have been made to prior years to conform to the current year’s presentation. All significant intercompany balances and transactions have been eliminated. The results of operations of companies since their formation or acquisition are included in the consolidated financial statements. Events or transactions occurring subsequent to December 31, 2020, and prior to the filing of this Form 10-K, have been evaluated for potential recognition or disclosure herein.</span></div><div><span><br/></span></div><div><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:400;line-height:120%">The preparation of the financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Changes in circumstances could cause actual results to differ materially from those estimates.</span></div>
CY2018	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2020	us-gaap	Revenue Recognition Deferred Revenue RevenueRecognitionDeferredRevenue	<span style="color:#003366;font-family:'Arial',sans-serif;font-size:11pt;font-weight:700;line-height:120%">Unearned Revenue</span><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:400;line-height:120%"> Certain upfront policy charges on annuities are deferred as unearned revenue (included in other liabilities) and recognized in net earnings (included in other income) using the same assumptions and estimated gross profits used to amortize DPAC.</span>
CY2019	afg	Disclosure On Geographic Areas Property And Casualty Revenues Attributed To Foreign Countries DisclosureOnGeographicAreasPropertyAndCasualtyRevenuesAttributedToForeignCountries	0.07
CY2019Q1	us-gaap	Operating Lease Liability OperatingLeaseLiability	198000000	USD
CY2019Q1	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	174000000	USD
CY2019Q1	afg	Deferred Rentand Lease Incentives DeferredRentandLeaseIncentives	24000000	USD
CY2020	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	500000	shares
CY2019	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1100000	shares
CY2018	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1600000	shares
CY2019	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2020	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2020	afg	Maturity Period Of Short Term Investment Maximum MaturityPeriodOfShortTermInvestmentMaximum	P3M
CY2020	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	segment
CY2020	afg	Disclosure On Geographic Areas Property And Casualty Revenues Attributed To Foreign Countries DisclosureOnGeographicAreasPropertyAndCasualtyRevenuesAttributedToForeignCountries	0.05
CY2018	afg	Disclosure On Geographic Areas Property And Casualty Revenues Attributed To Foreign Countries DisclosureOnGeographicAreasPropertyAndCasualtyRevenuesAttributedToForeignCountries	0.07
CY2020Q4	us-gaap	Assets Assets	73566000000	USD
CY2019Q4	us-gaap	Assets Assets	70130000000	USD
CY2018Q4	us-gaap	Assets Assets	63456000000	USD
CY2020	afg	Revenues Before Realized Gains Losses RevenuesBeforeRealizedGainsLosses	7597000000	USD
CY2019	afg	Revenues Before Realized Gains Losses RevenuesBeforeRealizedGainsLosses	7950000000	USD
CY2018	afg	Revenues Before Realized Gains Losses RevenuesBeforeRealizedGainsLosses	7416000000	USD
CY2020	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	289000000	USD
CY2019	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	287000000	USD
CY2018	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	-266000000	USD
CY2020	afg	Realized Gains Losses On Disposal Of Subsidiaries RealizedGainsLossesOnDisposalOfSubsidiaries	23000000	USD
CY2019	afg	Realized Gains Losses On Disposal Of Subsidiaries RealizedGainsLossesOnDisposalOfSubsidiaries	0	USD
CY2018	afg	Realized Gains Losses On Disposal Of Subsidiaries RealizedGainsLossesOnDisposalOfSubsidiaries	0	USD
CY2020	us-gaap	Revenues Revenues	7909000000	USD
CY2019	us-gaap	Revenues Revenues	8237000000	USD
CY2018	us-gaap	Revenues Revenues	7150000000	USD
CY2020	afg	Operating Income Loss Before Realized Gains Losses And Income Taxes OperatingIncomeLossBeforeRealizedGainsLossesAndIncomeTaxes	536000000	USD
CY2019	afg	Operating Income Loss Before Realized Gains Losses And Income Taxes OperatingIncomeLossBeforeRealizedGainsLossesAndIncomeTaxes	821000000	USD
CY2018	afg	Operating Income Loss Before Realized Gains Losses And Income Taxes OperatingIncomeLossBeforeRealizedGainsLossesAndIncomeTaxes	905000000	USD
CY2020	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	289000000	USD
CY2019	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	287000000	USD
CY2018	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	-266000000	USD
CY2020	afg	Realized Gains Losses On Disposal Of Subsidiaries RealizedGainsLossesOnDisposalOfSubsidiaries	23000000	USD
CY2019	afg	Realized Gains Losses On Disposal Of Subsidiaries RealizedGainsLossesOnDisposalOfSubsidiaries	0	USD
CY2018	afg	Realized Gains Losses On Disposal Of Subsidiaries RealizedGainsLossesOnDisposalOfSubsidiaries	0	USD
CY2020	us-gaap	Operating Income Loss OperatingIncomeLoss	848000000	USD
CY2019	us-gaap	Operating Income Loss OperatingIncomeLoss	1108000000	USD
CY2018	us-gaap	Operating Income Loss OperatingIncomeLoss	639000000	USD
CY2020	afg	Number Of Internal Investment Professionals NumberOfInternalInvestmentProfessionals	20	professional
CY2020Q4	afg	Variable Annuity Assets Fair Value Disclosure VariableAnnuityAssetsFairValueDisclosure	664000000	USD
CY2020Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	51498000000	USD
CY2020Q4	us-gaap	Liabilities Fair Value Disclosure LiabilitiesFairValueDisclosure	8714000000	USD
CY2019Q4	afg	Variable Annuity Assets Fair Value Disclosure VariableAnnuityAssetsFairValueDisclosure	628000000	USD
CY2019Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	54893000000	USD
CY2019Q4	us-gaap	Liabilities Fair Value Disclosure LiabilitiesFairValueDisclosure	8311000000	USD
CY2020Q4	afg	Level Three Asset As Percentage Of Asset Measured At Fair Value LevelThreeAssetAsPercentageOfAssetMeasuredAtFairValue	0.07
CY2020Q4	afg	Percentage Of Level Three Assets That Were Priced Using Non Binding Broker Quotes PercentageOfLevelThreeAssetsThatWerePricedUsingNonBindingBrokerQuotes	0.40
CY2020Q4	afg	Level Three Assets That Were Priced Using Non Binding Broker Quotes LevelThreeAssetsThatWerePricedUsingNonBindingBrokerQuotes	1500000000	USD
CY2020Q4	afg	Level Three Assets That Were Priced By Pricing Services LevelThreeAssetsThatWerePricedByPricingServices	530000000	USD
CY2020Q4	afg	Percentage Of Level Three Assets That Were Priced By Pricing Services PercentageOfLevelThreeAssetsThatWerePricedByPricingServices	0.14
CY2020Q4	afg	Percentage Of Internally Developed Level Three Assets Compared To Total Level3 Assets PercentageOfInternallyDevelopedLevelThreeAssetsComparedToTotalLevel3Assets	0.46
CY2019Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	3841000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-42000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss	69000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	781000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales	606000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3	620000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Out Of Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3	957000000	USD
CY2020Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	3706000000	USD
CY2019Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	3730000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Earnings FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings	283000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Other Comprehensive Income FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInOtherComprehensiveIncome	0	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Issues FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues	242000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	322000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Liability Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersIntoLevel3	0	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Liability Transfers Out Of Level3 FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3	0	USD
CY2020Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	3933000000	USD
CY2018Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	3521000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-10000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss	75000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	1578000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales	565000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3	244000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Out Of Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3	1002000000	USD
CY2019Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	3841000000	USD
CY2018Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	2720000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Earnings FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings	919000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Other Comprehensive Income FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInOtherComprehensiveIncome	0	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Issues FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues	333000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	242000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Liability Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersIntoLevel3	0	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Liability Transfers Out Of Level3 FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3	0	USD
CY2019Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	3730000000	USD
CY2017Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	2290000000	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-21000000	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss	-39000000	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	1828000000	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales	482000000	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3	270000000	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Out Of Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3	325000000	USD
CY2018Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	3521000000	USD
CY2017Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	2542000000	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Earnings FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings	-204000000	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Other Comprehensive Income FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInOtherComprehensiveIncome	0	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Issues FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues	545000000	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	163000000	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Liability Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersIntoLevel3	0	USD
CY2018	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Liability Transfers Out Of Level3 FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3	0	USD
CY2018Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	2720000000	USD
CY2020Q4	afg	Life Contingent Annuities LifeContingentAnnuities	1110000000	USD
CY2019Q4	afg	Life Contingent Annuities LifeContingentAnnuities	247000000	USD
CY2020	afg	Percentage Based On Unrealized Loss Of Available For Sale Fixed Maturities That Are In Unrealized Loss Position And Rated Investment Grade PercentageBasedOnUnrealizedLossOfAvailableForSaleFixedMaturitiesThatAreInUnrealizedLossPositionAndRatedInvestmentGrade	0.76
CY2020	afg	Percentage Based On Fair Value Of Available For Sale Fixed Maturities That Are In Unrealized Loss Position And Rated Investment Grade PercentageBasedOnFairValueOfAvailableForSaleFixedMaturitiesThatAreInUnrealizedLossPositionAndRatedInvestmentGrade	0.88
CY2019Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0	USD
CY2020	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Purchased With Credit Deterioration Increase DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease	1000000	USD
CY2020	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Not Previously Recorded DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded	68000000	USD
CY2020	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Not To Sell Before Recovery Credit Loss Previously Recorded Expense Reversal DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal	-22000000	USD
CY2020	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Securities Sold DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold	7000000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	40000000	USD
CY2020Q4	afg	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Pretax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentPretax	1589000000	USD
CY2020Q4	afg	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Deferred Tax And Non Controlling Interest AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentDeferredTaxAndNonControllingInterest	334000000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	1255000000	USD
CY2019Q4	afg	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Pretax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentPretax	1091000000	USD
CY2019Q4	afg	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Deferred Tax And Non Controlling Interest AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentDeferredTaxAndNonControllingInterest	229000000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	862000000	USD
CY2020	us-gaap	Gross Investment Income Operating GrossInvestmentIncomeOperating	2161000000	USD
CY2019	us-gaap	Gross Investment Income Operating GrossInvestmentIncomeOperating	2325000000	USD
CY2018	us-gaap	Gross Investment Income Operating GrossInvestmentIncomeOperating	2116000000	USD
CY2020	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	29000000	USD
CY2019	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	22000000	USD
CY2018	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	22000000	USD
CY2020	us-gaap	Net Investment Income NetInvestmentIncome	2132000000	USD
CY2019	us-gaap	Net Investment Income NetInvestmentIncome	2303000000	USD
CY2018	us-gaap	Net Investment Income NetInvestmentIncome	2094000000	USD
CY2020Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	351000000	USD
CY2019Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	577000000	USD
CY2017Q4	us-gaap	Deferred Policy Acquisition Costs And Value Of Business Acquired DeferredPolicyAcquisitionCostsAndValueOfBusinessAcquired	1216000000	USD
CY2018	us-gaap	Deferred Policy Acquisition Costs And Present Value Of Future Profits Additions DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAdditions	940000000	USD
CY2018	us-gaap	Deferred Policy Acquisition Costs And Present Value Of Future Profits Amortization1 DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAmortization1	908000000	USD
CY2018	afg	Deferred Policy Acquisition Costs And Present Value Of Future Profits Amortization Expense Effect Of Adjustments To Estimated Gross Profit DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAmortizationExpenseEffectOfAdjustmentsToEstimatedGrossProfit	-29000000	USD
CY2018	afg	Deferred Policy Acquisition Costs And Present Value Of Future Profits Amortization Expense Net Investment Gains Losses DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAmortizationExpenseNetInvestmentGainsLosses	-15000000	USD
CY2018	afg	Deferred Policy Acquisition Costs And Present Value Of Future Profits Foreign Currency Translation Adjustment DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsForeignCurrencyTranslationAdjustment	-2000000	USD
CY2018	afg	Deferred Policy Acquisition Costsand Present Valueof Future Profits Changein Unrealized Investment Gain Loss DeferredPolicyAcquisitionCostsandPresentValueofFutureProfitsChangeinUnrealizedInvestmentGainLoss	392000000	USD
CY2018Q4	us-gaap	Deferred Policy Acquisition Costs And Value Of Business Acquired DeferredPolicyAcquisitionCostsAndValueOfBusinessAcquired	1682000000	USD
CY2019	us-gaap	Deferred Policy Acquisition Costs And Present Value Of Future Profits Additions DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAdditions	952000000	USD
CY2019	us-gaap	Deferred Policy Acquisition Costs And Present Value Of Future Profits Amortization1 DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAmortization1	860000000	USD
CY2019	afg	Deferred Policy Acquisition Costs And Present Value Of Future Profits Amortization Expense Effect Of Adjustments To Estimated Gross Profit DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAmortizationExpenseEffectOfAdjustmentsToEstimatedGrossProfit	77000000	USD
CY2019	afg	Deferred Policy Acquisition Costs And Present Value Of Future Profits Amortization Expense Net Investment Gains Losses DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAmortizationExpenseNetInvestmentGainsLosses	-9000000	USD
CY2019	afg	Deferred Policy Acquisition Costs And Present Value Of Future Profits Foreign Currency Translation Adjustment DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsForeignCurrencyTranslationAdjustment	0	USD
CY2019	afg	Deferred Policy Acquisition Costsand Present Valueof Future Profits Changein Unrealized Investment Gain Loss DeferredPolicyAcquisitionCostsandPresentValueofFutureProfitsChangeinUnrealizedInvestmentGainLoss	-669000000	USD
CY2019Q4	us-gaap	Deferred Policy Acquisition Costs And Value Of Business Acquired DeferredPolicyAcquisitionCostsAndValueOfBusinessAcquired	1037000000	USD
CY2020	us-gaap	Deferred Policy Acquisition Costs And Present Value Of Future Profits Additions DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAdditions	703000000	USD
CY2020	us-gaap	Deferred Policy Acquisition Costs And Present Value Of Future Profits Amortization1 DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAmortization1	757000000	USD
CY2018	afg	Number Of Collateralized Loan Obligation Entities Substantially Liquidated During The Period NumberOfCollateralizedLoanObligationEntitiesSubstantiallyLiquidatedDuringThePeriod	2	collateralizedloanobligation
CY2020	afg	Deferred Policy Acquisition Costs And Present Value Of Future Profits Amortization Expense Effect Of Adjustments To Estimated Gross Profit DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAmortizationExpenseEffectOfAdjustmentsToEstimatedGrossProfit	114000000	USD
CY2020	afg	Deferred Policy Acquisition Costs And Present Value Of Future Profits Amortization Expense Net Investment Gains Losses DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsAmortizationExpenseNetInvestmentGainsLosses	41000000	USD
CY2020	afg	Deferred Policy Acquisition Costs And Present Value Of Future Profits Foreign Currency Translation Adjustment DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsForeignCurrencyTranslationAdjustment	0	USD
CY2020	afg	Deferred Policy Acquisition Costs And Present Value Of Future Profits Other DeferredPolicyAcquisitionCostsAndPresentValueOfFutureProfitsOther	-10000000	USD
CY2020	afg	Deferred Policy Acquisition Costsand Present Valueof Future Profits Changein Unrealized Investment Gain Loss DeferredPolicyAcquisitionCostsandPresentValueofFutureProfitsChangeinUnrealizedInvestmentGainLoss	-272000000	USD
CY2020Q4	us-gaap	Deferred Policy Acquisition Costs And Value Of Business Acquired DeferredPolicyAcquisitionCostsAndValueOfBusinessAcquired	546000000	USD
CY2020Q4	afg	Accumulated Amortization Of Present Value Of Future Profits AccumulatedAmortizationOfPresentValueOfFutureProfits	160000000	USD
CY2019Q4	afg	Accumulated Amortization Of Present Value Of Future Profits AccumulatedAmortizationOfPresentValueOfFutureProfits	154000000	USD
CY2020	afg	Percentage Of Investment Of Most Subordinate Debt Tranche Of Variable Interest Entity Minimum PercentageOfInvestmentOfMostSubordinateDebtTrancheOfVariableInterestEntityMinimum	0.150
CY2020	afg	Percentage Of Investment Of Most Subordinate Debt Tranche Of Variable Interest Entity Maximum PercentageOfInvestmentOfMostSubordinateDebtTrancheOfVariableInterestEntityMaximum	1.000
CY2020	afg	Number Of Collateralized Loan Obligation Entities NumberOfCollateralizedLoanObligationEntities	12	collateralizedloanobligation
CY2020	afg	Face Amount Of Managed Investment Entities Liabilities Purchased By Subsidiaries After Issuance Date FaceAmountOfManagedInvestmentEntitiesLiabilitiesPurchasedBySubsidiariesAfterIssuanceDate	57000000	USD
CY2020	afg	Amount Paid By Subsidiaries To Purchase Managed Investment Entities Liabilities After Issuance Date. AmountPaidBySubsidiariesToPurchaseManagedInvestmentEntitiesLiabilitiesAfterIssuanceDate.	39000000	USD
CY2020	afg	Proceeds Received By Subsidiaries Relatedto Salesand Redemptionsof Managed Investment Entities Liabilities ProceedsReceivedBySubsidiariesRelatedtoSalesandRedemptionsofManagedInvestmentEntitiesLiabilities	2000000	USD
CY2018	afg	Face Amount Of Managed Investment Entities Liabilities Purchased By Subsidiaries After Issuance Date FaceAmountOfManagedInvestmentEntitiesLiabilitiesPurchasedBySubsidiariesAfterIssuanceDate	7000000	USD
CY2018	afg	Amount Paid By Subsidiaries To Purchase Managed Investment Entities Liabilities After Issuance Date. AmountPaidBySubsidiariesToPurchaseManagedInvestmentEntitiesLiabilitiesAfterIssuanceDate.	7000000	USD
CY2018	afg	Proceeds Received By Subsidiaries Relatedto Salesand Redemptionsof Managed Investment Entities Liabilities ProceedsReceivedBySubsidiariesRelatedtoSalesandRedemptionsofManagedInvestmentEntitiesLiabilities	45000000	USD
CY2020	afg	Gain Loss On Change In Fair Value Of Assets Of Variable Interest Entities GainLossOnChangeInFairValueOfAssetsOfVariableInterestEntities	-69000000	USD
CY2019	afg	Gain Loss On Change In Fair Value Of Assets Of Variable Interest Entities GainLossOnChangeInFairValueOfAssetsOfVariableInterestEntities	80000000	USD
CY2018	afg	Gain Loss On Change In Fair Value Of Assets Of Variable Interest Entities GainLossOnChangeInFairValueOfAssetsOfVariableInterestEntities	-189000000	USD
CY2020	afg	Gain Loss On Change In Fair Value Of Liabilities Of Variable Interest Entities GainLossOnChangeInFairValueOfLiabilitiesOfVariableInterestEntities	30000000	USD
CY2019	afg	Gain Loss On Change In Fair Value Of Liabilities Of Variable Interest Entities GainLossOnChangeInFairValueOfLiabilitiesOfVariableInterestEntities	-110000000	USD
CY2018	afg	Gain Loss On Change In Fair Value Of Liabilities Of Variable Interest Entities GainLossOnChangeInFairValueOfLiabilitiesOfVariableInterestEntities	168000000	USD
CY2020	afg	Management Fees Paid By Variable Interest Entities ManagementFeesPaidByVariableInterestEntities	15000000	USD
CY2019	afg	Management Fees Paid By Variable Interest Entities ManagementFeesPaidByVariableInterestEntities	15000000	USD
CY2018	afg	Management Fees Paid By Variable Interest Entities ManagementFeesPaidByVariableInterestEntities	16000000	USD
CY2020	afg	Earnings Losses Of Variable Interest Entities Attributable To Shareholders EarningsLossesOfVariableInterestEntitiesAttributableToShareholders	-2000000	USD
CY2019	afg	Earnings Losses Of Variable Interest Entities Attributable To Shareholders EarningsLossesOfVariableInterestEntitiesAttributableToShareholders	4000000	USD
CY2018	afg	Earnings Losses Of Variable Interest Entities Attributable To Shareholders EarningsLossesOfVariableInterestEntitiesAttributableToShareholders	7000000	USD
CY2020Q4	afg	Difference Between Aggregate Unpaid Principal Balance And Fair Value Of Variable Interest Entity Investments DifferenceBetweenAggregateUnpaidPrincipalBalanceAndFairValueOfVariableInterestEntityInvestments	150000000	USD
CY2019Q4	afg	Difference Between Aggregate Unpaid Principal Balance And Fair Value Of Variable Interest Entity Investments DifferenceBetweenAggregateUnpaidPrincipalBalanceAndFairValueOfVariableInterestEntityInvestments	146000000	USD
CY2020Q4	afg	Difference Between Aggregate Unpaid Principal Balance And Fair Value Of Variable Interest Entity Debt DifferenceBetweenAggregateUnpaidPrincipalBalanceAndFairValueOfVariableInterestEntityDebt	141000000	USD
CY2019Q4	afg	Difference Between Aggregate Unpaid Principal Balance And Fair Value Of Variable Interest Entity Debt DifferenceBetweenAggregateUnpaidPrincipalBalanceAndFairValueOfVariableInterestEntityDebt	129000000	USD
CY2020Q4	afg	Carrying Amount Of Variable Interest Entity Loans In Default CarryingAmountOfVariableInterestEntityLoansInDefault	11000000	USD
CY2019Q4	afg	Carrying Amount Of Variable Interest Entity Loans In Default CarryingAmountOfVariableInterestEntityLoansInDefault	10000000	USD
CY2020Q4	afg	Aggregateunpaidprincipalbalanceofvariableinterestentityloansindefault Aggregateunpaidprincipalbalanceofvariableinterestentityloansindefault	28000000	USD
CY2019Q4	afg	Aggregateunpaidprincipalbalanceofvariableinterestentityloansindefault Aggregateunpaidprincipalbalanceofvariableinterestentityloansindefault	25000000	USD
CY2017Q4	us-gaap	Goodwill Goodwill	199000000	USD
CY2018	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	8000000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	207000000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	207000000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	207000000	USD
CY2018Q4	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	8000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	34000000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	43000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	62000000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	50000000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	12000000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11000000	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	9000000	USD
CY2020	us-gaap	Acquired Finite Lived Intangible Assets Weighted Average Useful Life AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife	P3Y
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	6000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	4000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	4000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	4000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	4000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	12000000	USD
CY2020Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	1993000000	USD
CY2020Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	30000000	USD
CY2020Q4	us-gaap	Long Term Debt LongTermDebt	1963000000	USD
CY2019Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	1493000000	USD
CY2019Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	20000000	USD
CY2019Q4	us-gaap	Long Term Debt LongTermDebt	1473000000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	0	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	0	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	0	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	0	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	0	USD
CY2020	us-gaap	Interest Paid InterestPaid	83000000	USD
CY2019	us-gaap	Interest Paid InterestPaid	65000000	USD
CY2018	us-gaap	Interest Paid InterestPaid	59000000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	139000000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	158000000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	159000000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	180000000	USD
CY2020Q4	afg	Deferred Rentand Lease Incentives DeferredRentandLeaseIncentives	20000000	USD
CY2019Q4	afg	Deferred Rentand Lease Incentives DeferredRentandLeaseIncentives	22000000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	47000000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	46000000	USD
CY2020	us-gaap	Short Term Lease Cost ShortTermLeaseCost	0	USD
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	1000000	USD
CY2020	us-gaap	Lease Cost LeaseCost	47000000	USD
CY2019	us-gaap	Lease Cost LeaseCost	47000000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	50000000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	49000000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	25000000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	19000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	43000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	35000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	29000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	23000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	20000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	28000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	178000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	19000000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	159000000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y4M24D
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.039
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Rights ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights	20% per year commencing one year after grant
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Expiration Period SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod	P10Y
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	1917790	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	50.93
CY2020	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	328471	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	43.69
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	225	shares
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice	63.15
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	1589094	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	52.43
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P2Y9M18D
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	56000000	USD
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	1589094	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	52.43
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P2Y9M18D
CY2020Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	56000000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	17000000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	46000000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	57000000	USD
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	14000000	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	31000000	USD
CY2018	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	29000000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Exercise Of Stock Options EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions	3000000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Exercise Of Stock Options EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions	8000000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Exercise Of Stock Options EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions	9000000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	20000000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	23000000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	23000000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	9000000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	13000000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	13000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	848000000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	1108000000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	639000000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	178000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	233000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	134000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2020	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	12000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.01
CY2019	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	14000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.01
CY2018	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	13000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.02
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-4000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-8000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	-0.01
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-8000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	-0.01
CY2020	us-gaap	Income Tax Reconciliation Deductions Dividends IncomeTaxReconciliationDeductionsDividends	3000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Deductions Dividends EffectiveIncomeTaxRateReconciliationDeductionsDividends	0
CY2019	us-gaap	Income Tax Reconciliation Deductions Dividends IncomeTaxReconciliationDeductionsDividends	4000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Deductions Dividends EffectiveIncomeTaxRateReconciliationDeductionsDividends	0
CY2018	us-gaap	Income Tax Reconciliation Deductions Dividends IncomeTaxReconciliationDeductionsDividends	4000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Deductions Dividends EffectiveIncomeTaxRateReconciliationDeductionsDividends	0.01
CY2020	us-gaap	Income Tax Reconciliation Prior Year Income Taxes IncomeTaxReconciliationPriorYearIncomeTaxes	-1000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	0
CY2019	us-gaap	Income Tax Reconciliation Prior Year Income Taxes IncomeTaxReconciliationPriorYearIncomeTaxes	-3000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	0
CY2018	us-gaap	Income Tax Reconciliation Prior Year Income Taxes IncomeTaxReconciliationPriorYearIncomeTaxes	-8000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	-0.01
CY2020	us-gaap	Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	2000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends EffectiveIncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	0
CY2019	us-gaap	Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	2000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends EffectiveIncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	0
CY2018	us-gaap	Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	3000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends EffectiveIncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	0.01
CY2020	afg	Effective Income Tax Rate Reconciliation Sale Of Subsidiaries EffectiveIncomeTaxRateReconciliationSaleOfSubsidiaries	-72000000	USD
CY2020	afg	Effective Income Tax Rate Reconciliation Sale Of Subsidiaries Percent EffectiveIncomeTaxRateReconciliationSaleOfSubsidiariesPercent	-0.08
CY2019	afg	Effective Income Tax Rate Reconciliation Sale Of Subsidiaries EffectiveIncomeTaxRateReconciliationSaleOfSubsidiaries	0	USD
CY2019	afg	Effective Income Tax Rate Reconciliation Sale Of Subsidiaries Percent EffectiveIncomeTaxRateReconciliationSaleOfSubsidiariesPercent	0
CY2018	afg	Effective Income Tax Rate Reconciliation Sale Of Subsidiaries EffectiveIncomeTaxRateReconciliationSaleOfSubsidiaries	0	USD
CY2018	afg	Effective Income Tax Rate Reconciliation Sale Of Subsidiaries Percent EffectiveIncomeTaxRateReconciliationSaleOfSubsidiariesPercent	0
CY2020	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-117000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	-0.14
CY2019	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	17000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.02
CY2018	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	11000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.02
CY2020	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	149000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.18
CY2019	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	4000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0
CY2018	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-2000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	5000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense EffectiveIncomeTaxRateReconciliationNondeductibleExpense	0.01
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	8000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense EffectiveIncomeTaxRateReconciliationNondeductibleExpense	0.01
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	7000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense EffectiveIncomeTaxRateReconciliationNondeductibleExpense	0.01
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	6000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.02
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	8000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0
CY2018	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	8000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.01
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	127000000	USD
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.15
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	239000000	USD
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.22
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	122000000	USD
CY2018	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.19
CY2020	afg	Effective Income Tax Rate Reconciliation Percent Excluding The Impact Of Subsidiaries Sold EffectiveIncomeTaxRateReconciliationPercentExcludingTheImpactOfSubsidiariesSold	0.21
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-131000000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-109000000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-69000000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	101000000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	250000000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	196000000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	6000000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	10000000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	8000000	USD
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	3000000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	2000000	USD
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	0	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	17000000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-23000000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-82000000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	127000000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	239000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	43000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	174000000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	122000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Domestic DeferredTaxAssetsOperatingLossCarryforwardsDomestic	15000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Domestic DeferredTaxAssetsOperatingLossCarryforwardsDomestic	19000000	USD
CY2020Q4	afg	Deferred Tax Assets Foreign Underwriting Losses DeferredTaxAssetsForeignUnderwritingLosses	6000000	USD
CY2019Q4	afg	Deferred Tax Assets Foreign Underwriting Losses DeferredTaxAssetsForeignUnderwritingLosses	118000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Capital Loss Carryforwards DeferredTaxAssetsCapitalLossCarryforwards	7000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Capital Loss Carryforwards DeferredTaxAssetsCapitalLossCarryforwards	0	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Policyholder Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsPolicyholderLiabilities	840000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Policyholder Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsPolicyholderLiabilities	875000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	104000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	93000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	48000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	43000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	1020000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	1148000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	29000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	140000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	991000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	1008000000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	763000000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	556000000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Policy Acquisition Cost DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost	71000000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Policy Acquisition Cost DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost	150000000	USD
CY2020Q4	afg	Deferred Tax Liabilities Tax Cutsand Jobs Actof2017 Discounted Reserves Transition Adjustment DeferredTaxLiabilitiesTaxCutsandJobsActof2017DiscountedReservesTransitionAdjustment	77000000	USD
CY2019Q4	afg	Deferred Tax Liabilities Tax Cutsand Jobs Actof2017 Discounted Reserves Transition Adjustment DeferredTaxLiabilitiesTaxCutsandJobsActof2017DiscountedReservesTransitionAdjustment	93000000	USD
CY2020Q4	afg	Deferred Tax Liabilities Real Estate Propertyand Equipment DeferredTaxLiabilitiesRealEstatePropertyandEquipment	37000000	USD
CY2019Q4	afg	Deferred Tax Liabilities Real Estate Propertyand Equipment DeferredTaxLiabilitiesRealEstatePropertyandEquipment	35000000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	948000000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	834000000	USD
CY2020Q4	us-gaap	Operating Loss Carryforwards Valuation Allowance OperatingLossCarryforwardsValuationAllowance	15000000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	0	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	0	USD
CY2020	us-gaap	Unrecognized Tax Benefits Income Tax Penalties Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense	0	USD
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	179000000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	278000000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	156000000	USD
CY2020Q1	us-gaap	Revenues Revenues	1275000000	USD
CY2020Q2	us-gaap	Revenues Revenues	1951000000	USD
CY2020Q3	us-gaap	Revenues Revenues	2060000000	USD
CY2020Q4	us-gaap	Revenues Revenues	2623000000	USD
CY2020	us-gaap	Revenues Revenues	7909000000	USD
CY2020Q1	us-gaap	Profit Loss ProfitLoss	-304000000	USD
CY2020Q2	us-gaap	Profit Loss ProfitLoss	167000000	USD
CY2020Q3	us-gaap	Profit Loss ProfitLoss	164000000	USD
CY2020Q4	us-gaap	Profit Loss ProfitLoss	694000000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	721000000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	-301000000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	177000000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	164000000	USD
CY2020Q4	us-gaap	Net Income Loss NetIncomeLoss	692000000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	732000000	USD
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-3.34
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.98
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.86
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	7.99
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	8.25
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-3.34
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.97
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.86
CY2020Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	7.93
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	8.20
CY2020Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	90300000	shares
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	89700000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	88200000	shares
CY2020Q4	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	86600000	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	88700000	shares
CY2020Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	90300000	shares
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	90000000.0	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	88500000	shares
CY2020Q4	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87200000	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	89200000	shares
CY2019Q1	us-gaap	Revenues Revenues	2024000000	USD
CY2019Q2	us-gaap	Revenues Revenues	1960000000	USD
CY2019Q3	us-gaap	Revenues Revenues	2123000000	USD
CY2019Q4	us-gaap	Revenues Revenues	2130000000	USD
CY2019	us-gaap	Revenues Revenues	8237000000	USD
CY2019Q1	us-gaap	Profit Loss ProfitLoss	326000000	USD
CY2019Q2	us-gaap	Profit Loss ProfitLoss	209000000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	143000000	USD
CY2019Q4	us-gaap	Profit Loss ProfitLoss	191000000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	869000000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	329000000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	210000000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	147000000	USD
CY2019Q4	us-gaap	Net Income Loss NetIncomeLoss	211000000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	897000000	USD
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.68
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.34
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.64
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.33
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	9.98
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.63
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.31
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.62
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.31
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	9.85
CY2019Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	89400000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	89700000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	90000000.0	shares
CY2019Q4	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	90200000	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	89900000	shares
CY2019Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	90700000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	91000000.0	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	91100000	shares
CY2019Q4	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	91300000	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	91000000.0	shares
CY2020Q1	afg	Impactof Unlocking Changesinthe Fair Valueof Derivativesand Changesinthe Stock Marketand Interest Ratesonthe Accountingfor Fi As ImpactofUnlockingChangesintheFairValueofDerivativesandChangesintheStockMarketandInterestRatesontheAccountingforFIAs	-38000000	USD
CY2020Q2	afg	Impactof Unlocking Changesinthe Fair Valueof Derivativesand Changesinthe Stock Marketand Interest Ratesonthe Accountingfor Fi As ImpactofUnlockingChangesintheFairValueofDerivativesandChangesintheStockMarketandInterestRatesontheAccountingforFIAs	-59000000	USD
CY2020Q3	afg	Impactof Unlocking Changesinthe Fair Valueof Derivativesand Changesinthe Stock Marketand Interest Ratesonthe Accountingfor Fi As ImpactofUnlockingChangesintheFairValueofDerivativesandChangesintheStockMarketandInterestRatesontheAccountingforFIAs	-43000000	USD
CY2020Q4	afg	Impactof Unlocking Changesinthe Fair Valueof Derivativesand Changesinthe Stock Marketand Interest Ratesonthe Accountingfor Fi As ImpactofUnlockingChangesintheFairValueofDerivativesandChangesintheStockMarketandInterestRatesontheAccountingforFIAs	-48000000	USD
CY2020	afg	Impactof Unlocking Changesinthe Fair Valueof Derivativesand Changesinthe Stock Marketand Interest Ratesonthe Accountingfor Fi As ImpactofUnlockingChangesintheFairValueofDerivativesandChangesintheStockMarketandInterestRatesontheAccountingforFIAs	-188000000	USD
CY2019Q1	afg	Impactof Unlocking Changesinthe Fair Valueof Derivativesand Changesinthe Stock Marketand Interest Ratesonthe Accountingfor Fi As ImpactofUnlockingChangesintheFairValueofDerivativesandChangesintheStockMarketandInterestRatesontheAccountingforFIAs	-11000000	USD
CY2019Q2	afg	Impactof Unlocking Changesinthe Fair Valueof Derivativesand Changesinthe Stock Marketand Interest Ratesonthe Accountingfor Fi As ImpactofUnlockingChangesintheFairValueofDerivativesandChangesintheStockMarketandInterestRatesontheAccountingforFIAs	-33000000	USD
CY2019Q3	afg	Impactof Unlocking Changesinthe Fair Valueof Derivativesand Changesinthe Stock Marketand Interest Ratesonthe Accountingfor Fi As ImpactofUnlockingChangesintheFairValueofDerivativesandChangesintheStockMarketandInterestRatesontheAccountingforFIAs	-27000000	USD
CY2019Q4	afg	Impactof Unlocking Changesinthe Fair Valueof Derivativesand Changesinthe Stock Marketand Interest Ratesonthe Accountingfor Fi As ImpactofUnlockingChangesintheFairValueofDerivativesandChangesintheStockMarketandInterestRatesontheAccountingforFIAs	24000000	USD
CY2019	afg	Impactof Unlocking Changesinthe Fair Valueof Derivativesand Changesinthe Stock Marketand Interest Ratesonthe Accountingfor Fi As ImpactofUnlockingChangesintheFairValueofDerivativesandChangesintheStockMarketandInterestRatesontheAccountingforFIAs	-47000000	USD
CY2020Q1	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	42000000	USD
CY2020Q2	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	77000000	USD
CY2020Q3	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	0	USD
CY2020Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	8000000	USD
CY2020	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	127000000	USD
CY2019Q1	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	45000000	USD
CY2019Q2	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	41000000	USD
CY2019Q3	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	12000000	USD
CY2019Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	45000000	USD
CY2019	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	143000000	USD
CY2020Q1	afg	Pretax Catastrophe Losses PretaxCatastropheLosses	9000000	USD
CY2020Q2	afg	Pretax Catastrophe Losses PretaxCatastropheLosses	26000000	USD
CY2020Q3	afg	Pretax Catastrophe Losses PretaxCatastropheLosses	57000000	USD
CY2020Q4	afg	Pretax Catastrophe Losses PretaxCatastropheLosses	38000000	USD
CY2020	afg	Pretax Catastrophe Losses PretaxCatastropheLosses	130000000	USD
CY2019Q1	afg	Pretax Catastrophe Losses PretaxCatastropheLosses	12000000	USD
CY2019Q2	afg	Pretax Catastrophe Losses PretaxCatastropheLosses	12000000	USD
CY2019Q3	afg	Pretax Catastrophe Losses PretaxCatastropheLosses	22000000	USD
CY2019Q4	afg	Pretax Catastrophe Losses PretaxCatastropheLosses	15000000	USD
CY2019	afg	Pretax Catastrophe Losses PretaxCatastropheLosses	61000000	USD
CY2020Q1	afg	Pretax Covid19 Related Losses PretaxCOVID19RelatedLosses	10000000	USD
CY2020Q2	afg	Pretax Covid19 Related Losses PretaxCOVID19RelatedLosses	105000000	USD
CY2020Q4	us-gaap	Assets Held By Insurance Regulators AssetsHeldByInsuranceRegulators	1120000000	USD
CY2020Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	308000000	USD
CY2020Q4	afg	Undrawn Letters Of Credit Collateralized UndrawnLettersOfCreditCollateralized	0	USD
CY2020	us-gaap	Workers Compensation Discount Percent WorkersCompensationDiscountPercent	0.035
CY2019	us-gaap	Workers Compensation Discount Percent WorkersCompensationDiscountPercent	0.045
CY2020Q4	us-gaap	Workers Compensation Discount Amount WorkersCompensationDiscountAmount	9000000	USD
CY2019Q4	us-gaap	Workers Compensation Discount Amount WorkersCompensationDiscountAmount	12000000	USD
CY2020	us-gaap	Schedule Of Liability For Unpaid Claims And Claims Adjustment Expense ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense	<div><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:400;line-height:120%">The following table provides an analysis of changes in the liability for losses and loss adjustment expenses over the past three years (in millions):</span><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:700;line-height:120%"> </span></div><div style="margin-top:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:65.712%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:9.572%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.384%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:9.572%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.384%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:9.576%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:8pt;font-weight:400;line-height:100%">2020</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:8pt;font-weight:400;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:8pt;font-weight:400;line-height:100%">2018</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Balance at beginning of period</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">10,232 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">$</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">9,741 </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:'Arial',sans-serif;font-size:9pt;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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">9,678 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Less reinsurance recoverables, net of allowance</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">3,024 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">2,942 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">2,957 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Net liability at beginning of period</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">7,208 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">6,799 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">6,721 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Provision for losses and LAE occurring in the current year</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">3,398 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">3,414 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">3,195 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Net increase (decrease) in the provision for claims of prior years:</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12.25pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Special A&E charges</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">47 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">18 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">18 </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 2px 12.25pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Neon exited lines</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">19 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">7 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">— </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 12.25pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(193)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(168)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(210)</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 2px 25.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Total losses and LAE incurred</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">3,271 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">3,271 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">3,003 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Payments for losses and LAE of:</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 12.25pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(990)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(1,076)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(963)</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 12.25pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(1,766)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(1,790)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(1,639)</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 2px 25.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Total payments</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(2,756)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(2,866)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(2,602)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Reserves of businesses disposed ()</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(449)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">— </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(319)</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Foreign currency translation and 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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">1 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">(4)</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;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Net liability at end of period</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">7,275 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">7,208 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">6,799 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Add back reinsurance recoverables, net of allowance</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">3,117 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">3,024 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">2,942 </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;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">Gross unpaid losses and LAE included in the balance sheet</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:'Arial',sans-serif;font-size:9pt;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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">10,392 </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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">10,232 </span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">$</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:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:100%">9,741 </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><div style="margin-top:12pt;padding-left:22.5pt;text-indent:-22.5pt"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:400;line-height:120%">()</span><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:400;line-height:120%;padding-left:12.49pt">Reflects the December 31, 2020 sale of Neon (see </span><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-style:italic;font-weight:400;line-height:120%">Note B</span><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:400;line-height:120%"> </span><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-style:italic;font-weight:400;line-height:120%">— “Acquisitions and Sale of Businesses”</span><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:400;line-height:120%">) and the reinsurance to close transactions at Neon, which settled in early 2018 (discussed below).</span></div>
CY2019Q4	us-gaap	Liability For Claims And Claims Adjustment Expense Property Casualty Liability LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability	10232000000	USD
CY2018Q4	us-gaap	Liability For Claims And Claims Adjustment Expense Property Casualty Liability LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability	9741000000	USD
CY2017Q4	us-gaap	Liability For Claims And Claims Adjustment Expense Property Casualty Liability LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability	9678000000	USD
CY2019Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	3024000000	USD
CY2018Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	2942000000	USD
CY2017Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	2957000000	USD
CY2019Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	7208000000	USD
CY2018Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	6799000000	USD
CY2017Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	6721000000	USD
CY2020	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	3398000000	USD
CY2019	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	3414000000	USD
CY2018	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	3195000000	USD
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	3271000000	USD
CY2019	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	3271000000	USD
CY2018	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	3003000000	USD
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	990000000	USD
CY2019	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	1076000000	USD
CY2018	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	963000000	USD
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	1766000000	USD
CY2019	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	1790000000	USD
CY2018	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	1639000000	USD
CY2020	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	2756000000	USD
CY2019	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	2866000000	USD
CY2018	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	2602000000	USD
CY2020	afg	Liabilityfor Unpaid Claimsand Claims Adjustment Expense Business Disposals LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseBusinessDisposals	-449000000	USD
CY2019	afg	Liabilityfor Unpaid Claimsand Claims Adjustment Expense Business Disposals LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseBusinessDisposals	0	USD
CY2018	afg	Liabilityfor Unpaid Claimsand Claims Adjustment Expense Business Disposals LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseBusinessDisposals	-319000000	USD
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Translation Gain Loss LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCurrencyTranslationGainLoss	1000000	USD
CY2019	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Translation Gain Loss LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCurrencyTranslationGainLoss	4000000	USD
CY2018	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Translation Gain Loss LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCurrencyTranslationGainLoss	-4000000	USD
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	7275000000	USD
CY2019Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	7208000000	USD
CY2018Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	6799000000	USD
CY2020Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	3117000000	USD
CY2019Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	3024000000	USD
CY2018Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	2942000000	USD
CY2020Q4	us-gaap	Liability For Claims And Claims Adjustment Expense Property Casualty Liability LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability	10392000000	USD
CY2019Q4	us-gaap	Liability For Claims And Claims Adjustment Expense Property Casualty Liability LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability	10232000000	USD
CY2018Q4	us-gaap	Liability For Claims And Claims Adjustment Expense Property Casualty Liability LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability	9741000000	USD
CY2020	afg	Pretax Covid19 Related Losses PretaxCOVID19RelatedLosses	115000000	USD
CY2020Q4	afg	Long Term Care Insurance Reserves LongTermCareInsuranceReserves	52000000	USD
CY2019Q4	afg	Long Term Care Insurance Reserves LongTermCareInsuranceReserves	46000000	USD
CY2020Q4	afg	Dividend Payments Without Violating Most Restrictive Debt Covenants DividendPaymentsWithoutViolatingMostRestrictiveDebtCovenants	2000000000.0	USD
CY2020	us-gaap	Reinsurance Retention Policy Excess Retention Amount Reinsured ReinsuranceRetentionPolicyExcessRetentionAmountReinsured	50000000	USD
CY2020	us-gaap	Reinsurance Retention Policy Amount Retained ReinsuranceRetentionPolicyAmountRetained	100000000	USD
CY2019Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	18000000	USD
CY2020Q1	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	6000000	USD
CY2020	us-gaap	Reinsurance Recoverable Credit Loss Expense Reversal ReinsuranceRecoverableCreditLossExpenseReversal	2000000	USD
CY2020	us-gaap	Reinsurance Loss On Uncollectible Accounts In Period Amount ReinsuranceLossOnUncollectibleAccountsInPeriodAmount	0	USD
CY2020	afg	Reinsurance Recoverable Allowance For Credit Loss Businesses Disposed ReinsuranceRecoverableAllowanceForCreditLossBusinessesDisposed	-1000000	USD
CY2020Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	13000000	USD
CY2020Q4	afg	Liabilities For Excess Benefits Expected To Be Paid On Future Deaths And Annuitizations LiabilitiesForExcessBenefitsExpectedToBePaidOnFutureDeathsAndAnnuitizations	260000000	USD
CY2019Q4	afg	Liabilities For Excess Benefits Expected To Be Paid On Future Deaths And Annuitizations LiabilitiesForExcessBenefitsExpectedToBePaidOnFutureDeathsAndAnnuitizations	232000000	USD
CY2020Q4	us-gaap	Liabilities For Guarantees On Long Duration Contracts Guaranteed Benefit Liability Gross LiabilitiesForGuaranteesOnLongDurationContractsGuaranteedBenefitLiabilityGross	817000000	USD
CY2019Q4	us-gaap	Liabilities For Guarantees On Long Duration Contracts Guaranteed Benefit Liability Gross LiabilitiesForGuaranteesOnLongDurationContractsGuaranteedBenefitLiabilityGross	625000000	USD
CY2020Q4	afg	Liabilities For Excess Benefits Expected To Be Paid On Accrued Persistency And Premium Bonuses LiabilitiesForExcessBenefitsExpectedToBePaidOnAccruedPersistencyAndPremiumBonuses	0	USD
CY2019Q4	afg	Liabilities For Excess Benefits Expected To Be Paid On Accrued Persistency And Premium Bonuses LiabilitiesForExcessBenefitsExpectedToBePaidOnAccruedPersistencyAndPremiumBonuses	1000000	USD
CY2020Q4	afg	Aggregate Guaranteed Minimum Death Benefit Value On Variable Annuity Policies In Force AggregateGuaranteedMinimumDeathBenefitValueOnVariableAnnuityPoliciesInForce	11000000	USD
CY2019Q4	afg	Aggregate Guaranteed Minimum Death Benefit Value On Variable Annuity Policies In Force AggregateGuaranteedMinimumDeathBenefitValueOnVariableAnnuityPoliciesInForce	13000000	USD
CY2020Q4	afg	Unfunded Commitments To Limited Partnerships UnfundedCommitmentsToLimitedPartnerships	993000000	USD
CY2020	us-gaap	Other Postretirement Benefit Expense OtherPostretirementBenefitExpense	41000000	USD
CY2019	us-gaap	Other Postretirement Benefit Expense OtherPostretirementBenefitExpense	39000000	USD
CY2018	us-gaap	Other Postretirement Benefit Expense OtherPostretirementBenefitExpense	37000000	USD
CY2020Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	546000000	USD
CY2020Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	53572000000	USD
CY2020Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	2803000000	USD
CY2020	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	5118000000	USD
CY2020	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	2132000000	USD
CY2018	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	4889000000	USD
CY2020	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	4503000000	USD
CY2020	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	866000000	USD
CY2020	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	1692000000	USD
CY2020	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	5017000000	USD
CY2019Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	1037000000	USD
CY2019Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	51250000000	USD
CY2019Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	2830000000	USD
CY2019	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	5207000000	USD
CY2019	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	2303000000	USD
CY2019	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	4458000000	USD
CY2019	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	923000000	USD
CY2019	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	1748000000	USD
CY2019	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	5345000000	USD
CY2018Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	1682000000	USD
CY2018Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	46992000000	USD
CY2018Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	2595000000	USD
CY2018	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	2094000000	USD
CY2018	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	4041000000	USD
CY2018	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	860000000	USD
CY2018	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	1610000000	USD
CY2018	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	5026000000	USD

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$AFG
AMERICAN FINANCIAL GROUP INC Stock $afg

2020 Q4 Form 10-K Financial Statement

#000104204621000011 Filed on February 25, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AFG AMERICAN FINANCIAL GROUP INC Stock $afg

2020 Q4 Form 10-K Financial Statement

#000104204621000011 Filed on February 25, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AFG
AMERICAN FINANCIAL GROUP INC Stock $afg