XML 59 R40.htm IDEA: XBRL DOCUMENT
v3.20.1

Fair Value Measurements - Narrative (Details) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2020 USD ($) basispoint professional security | Dec. 31, 2019 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
AFG's internal investment professionals | professional | 20 |
Level 3 assets as a percentage of total assets measured at fair value | 7.00% |
Percentage of level 3 assets that were priced using non-binding broker quotes | 43.00% |
Level 3 assets that were priced using non-binding broker quotes | $ | $ 1,520 |
Percent of spreads between 200 and 700 basis points | 70.00% |
Life contingent annuities | $ | $ 245 | $ 247
Fixed-indexed and variable-indexed annuities (embedded derivative), majority of future years | Minimum |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Unobservable input surrenders used in Level 3 fair value determination | 7.00% |
Fixed-indexed and variable-indexed annuities (embedded derivative), majority of future years | Maximum |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Unobservable input surrenders used in Level 3 fair value determination | 10.00% |
Fixed-indexed and variable-indexed annuities (embedded derivative) |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fair value of derivatives in annuity benefits accumulated measured using a discounted cash flow approach | $ | $ 3,100 |
Fixed-indexed and variable-indexed annuities (embedded derivative) | Minimum |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Unobservable input surrenders used in Level 3 fair value determination | 4.00% |
Fixed-indexed and variable-indexed annuities (embedded derivative) | Maximum |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Unobservable input surrenders used in Level 3 fair value determination | 21.00% |
Level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Internally developed level 3 assets | $ | $ 1,630 |
Third party pricing model | Fixed maturities | Level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Internally developed level 3 assets | $ | $ 727 |
Securities priced using a third-party model | security | 37 |
Basis points credit spread applied by management using third party model | basispoint | 414 |
Third party pricing model | Fixed maturities | Level 3 | Minimum |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Basis points credit spread applied by management using third party model | basispoint | 200 |
Third party pricing model | Fixed maturities | Level 3 | Maximum |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Basis points credit spread applied by management using third party model | basispoint | 700 |
Credit spread used in pricing model | Third party pricing model | Fixed maturities | Level 3 | Minimum |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Basis points credit spread applied by management using third party model | basispoint | 53 |
Credit spread used in pricing model | Third party pricing model | Fixed maturities | Level 3 | Maximum |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Basis points credit spread applied by management using third party model | basispoint | 1,253 |

X
- Definition Risk associated with risk of surrenders, expressed as a percentage, used as an input to measure fair value. + References No definition available. + Details
Name: | afg_FairValueInputsSurrenders
Namespace Prefix: | afg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Level 3 assets in which the fair value was developed internally. + References No definition available. + Details
Name: | afg_InternallyDevelopedLevel3Assets
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Level Three Asset As Percentage Of Asset Measured At Fair Value. + References No definition available. + Details
Name: | afg_LevelThreeAssetAsPercentageOfAssetMeasuredAtFairValue
Namespace Prefix: | afg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Level three assets that were priced using non-binding broker quotes. + References No definition available. + Details
Name: | afg_LevelThreeAssetsThatWerePricedUsingNonBindingBrokerQuotes
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financial liabilities on annuities in the payout phase that are contingent on the survival of the annuitant(s). + References No definition available. + Details
Name: | afg_LifeContingentAnnuities
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of internal investment professionals. + References No definition available. + Details
Name: | afg_NumberOfInternalInvestmentProfessionals
Namespace Prefix: | afg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of level 3 assets that were priced using non-binding broker quotes. + References No definition available. + Details
Name: | afg_PercentageOfLevelThreeAssetsThatWerePricedUsingNonBindingBrokerQuotes
Namespace Prefix: | afg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percent of spreads between 400 and 700 basis points used in the third party pricing model. + References No definition available. + Details
Name: | afg_PercentofSpreadsUsedinThirdPartyPricingModel
Namespace Prefix: | afg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of securities priced using a third-party model. + References No definition available. + Details
Name: | afg_SecuritiesPricedUsingThirdPartyModel
Namespace Prefix: | afg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Value of input used to measure investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13433-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313 + Details
Name: | us-gaap_DerivativeLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=afg_FixedIndexedandVariableIndexedAnnuitiesEmbeddedDerivativeMajorityofFutureYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=afg_FixedIndexedandVariableIndexedAnnuitiesEmbeddedDerivativesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=afg_ThirdPartyPricingModelMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_FixedMaturitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputCreditSpreadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |