XML 79 R57.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Fair Value Measurements - Narrative (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 USD ($) professional
Fair Value Measurements (Textual) [Abstract] |
AFG's internal investment professionals | professional | 20
Level 3 assets as a percentage of total assets measured at fair value | 6.00%
Percentage of level 3 assets that were priced using non-binding broker quotes | 15.00%
Level 3 assets that were priced using non-binding broker quotes | $ 142
Level 3 assets that were priced by pricing services. | $ 55
Percentage of Level 3 assets that were priced by pricing services | 6.00%
Percentage of Level 3 assets that were priced using a discounted cash flow approach | 55.00%
Level 3 assets that were priced using a discounted cash flow approach | $ 307
Percentage of equity securities in Level 3 priced using broker quotes and internal models | 26.00%
Equity securities in Level 3 priced using broker quotes and internal models | $ 144
Level 3 |
Fair Value Measurements (Textual) [Abstract] |
Internally developed Level 3 assets | $ 557
Percentage of internally developed Level 3 assets compared to total Level 3 assets | 60.00%
Level 3 | Continuing operations |
Fair Value Measurements (Textual) [Abstract] |
Percentage of equity investments in Level 3 assets that do not qualify for equity accounting | 18.00%
Equity investments in Level 3 assets that do not qualify for equity accounting | $ 166

X
- Definition Fair Value Measurements. + References No definition available. + Details
Name: | afg_FairValueMeasurementsTextualAbstract
Namespace Prefix: | afg_
Data Type: | xbrli:stringItemType
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: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Level three assets, equity investments that do not qualify for equity accounting + References No definition available. + Details
Name: | afg_LevelThreeAssetsEquityInvestmentsThatDoNotQualifyForEquityAccounting
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Level three assets, equity securities priced using broker quotes and internal models + References No definition available. + Details
Name: | afg_LevelThreeAssetsEquitySecuritiesPricedUsingBrokerQuotesAndInternalModels
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Level three assets that were priced by pricing services. + References No definition available. + Details
Name: | afg_LevelThreeAssetsThatWerePricedByPricingServices
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Level three assets that were priced using a discounted cash flow approach. + References No definition available. + Details
Name: | afg_LevelThreeAssetsThatWerePricedUsingADiscountedCashFlowApproach
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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: | 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 Internally Developed Level Three Assets Compared to Total Level 3 Assets + References No definition available. + Details
Name: | afg_PercentageOfInternallyDevelopedLevelThreeAssetsComparedToTotalLevel3Assets
Namespace Prefix: | afg_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of Level three assets, equity investments that do not qualify for equity accounting + References No definition available. + Details
Name: | afg_PercentageOfLevelThreeAssetsEquityInvestmentsThatDoNotQualifyForEquityAccounting
Namespace Prefix: | afg_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of level three assets, equity securities priced using broker quotes and internal models + References No definition available. + Details
Name: | afg_PercentageOfLevelThreeAssetsEquitySecuritiesPricedUsingBrokerQuotesAndInternalModels
Namespace Prefix: | afg_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage Of Level Three Assets That Were Priced By Pricing Services + References No definition available. + Details
Name: | afg_PercentageOfLevelThreeAssetsThatWerePricedByPricingServices
Namespace Prefix: | afg_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of level three assets that were priced using a discounted cash flow approach. + References No definition available. + Details
Name: | afg_PercentageOfLevelThreeAssetsThatWerePricedUsingADiscountedCashFlowApproach
Namespace Prefix: | afg_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

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: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

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

X
- Details
Name: | us-gaap_StatementOperatingActivitiesSegmentAxis=us-gaap_SegmentContinuingOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |