XML 102 R66.htm IDEA: XBRL DOCUMENT v2.4.1.9
Derivatives (Details Textual) (USD $)
In Millions, unless otherwise specified
 12 Months Ended 3 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Sep. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]        
Indexed annuities as a percentage of annuity benefits 50.00%afg_IndexedAnnuitiesAsPercentageOfAnnuityBenefits      
Carrying value of collateral received to support purchased call options $ 285us-gaap_DerivativeCollateralRightToReclaimCash      
Not Designated as Hedging Instrument [Member] | Interest rate swaptions [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Notional amount of derivative asset instrument outstanding 200us-gaap_DerivativeAssetNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateSwaptionMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		      
Payments to purchase swaptions 4afg_CumulativePaymentstoPurchaseDerivatives
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateSwaptionMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		      
Not Designated as Hedging Instrument [Member] | Annuity benefits [Member] | Fixed-indexed annuities (embedded derivative) [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
The portion of the change in fair value of the embedded derivative related to the unlocking of actuarial assumptions 58afg_DerivativeGainLossOnDerivativeAnnuityUnlocking
/ us-gaap_DerivativeInstrumentRiskAxis
= afg_FixedIndexedAnnuitiesEmbeddedDerivativeMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ us-gaap_IncomeStatementLocationAxis
= afg_AnnuitybenefitsMember		 2afg_DerivativeGainLossOnDerivativeAnnuityUnlocking
/ us-gaap_DerivativeInstrumentRiskAxis
= afg_FixedIndexedAnnuitiesEmbeddedDerivativeMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ us-gaap_IncomeStatementLocationAxis
= afg_AnnuitybenefitsMember		 36afg_DerivativeGainLossOnDerivativeAnnuityUnlocking
/ us-gaap_DerivativeInstrumentRiskAxis
= afg_FixedIndexedAnnuitiesEmbeddedDerivativeMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ us-gaap_IncomeStatementLocationAxis
= afg_AnnuitybenefitsMember		  
Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member] | Interest rate swaptions [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Contract term of derivative instrument       5 years
Notional amount of derivative instrument outstanding 401invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateSwaptionMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_CashFlowHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember		     431invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateSwaptionMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_CashFlowHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
Gain (loss) reclassified from AOCI into net investment income 2us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateSwaptionMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_CashFlowHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember		      
Maximum [Member] | Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member] | Interest rate swaptions [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Net derivatives, at fair value (are less than) $ (1)us-gaap_DerivativeFairValueOfDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateSwaptionMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_CashFlowHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		      
LIBOR [Member] | Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member] | Interest rate swaptions [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Description of variable interest rate of derivative instrument       one-month LIBOR