XML 54 R42.htm IDEA: XBRL DOCUMENT
v3.25.3

Fair Value Measurements - Changes in balances of Level 3 financial assets carried at fair value (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Financial assets, Beginning Balance | $ 1,062 | $ 1,382 | $ 1,096 | $ 1,230
Total realized/unrealized gains (losses) included in net earnings (loss) | 14 | 23 | 31 | 54
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 2 | 14 | 12 | 19
Purchases and issuances | 34 | 97 | 109 | 276
Sales and settlements | (98) | (53) | (193) | (85)
Transfer into Level 3 | 2 | 8 | 15 | 8
Transfer out of Level 3 | (12) | 0 | (66) | (31)
Financial assets, Ending Balance | 1,004 | 1,471 | 1,004 | 1,471
Fixed maturities |  |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Financial assets, Beginning Balance | 752 | 756 | 768 | 736
Total realized/unrealized gains (losses) included in net earnings (loss) | 14 | 5 | 15 | 3
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 2 | 14 | 12 | 19
Purchases and issuances | 25 | 42 | 80 | 114
Sales and settlements | (98) | (10) | (179) | (34)
Transfer into Level 3 | 2 | 8 | 8 | 8
Transfer out of Level 3 | (12) | 0 | (19) | (31)
Financial assets, Ending Balance | 685 | 815 | 685 | 815
State and municipal |  |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Financial assets, Beginning Balance | 6 | 2 | 1 | 2
Total realized/unrealized gains (losses) included in net earnings (loss) | 0 | 0 | 0 | 0
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 0 | 0 | 0
Purchases and issuances | 0 | 0 | 0 | 0
Sales and settlements | (1) | 0 | (1) | 0
Transfer into Level 3 | 0 | 0 | 5 | 0
Transfer out of Level 3 | 0 | 0 | 0 | 0
Financial assets, Ending Balance | 5 | 2 | 5 | 2
Residential MBS |  |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Financial assets, Beginning Balance | 1 | 2 | 1 | 2
Total realized/unrealized gains (losses) included in net earnings (loss) | 0 | 0 | 0 | 0
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 0 | 0 | 0
Purchases and issuances | 0 | 0 | 0 | 0
Sales and settlements | 0 | 0 | 0 | 0
Transfer into Level 3 | 2 | 0 | 2 | 0
Transfer out of Level 3 | 0 | 0 | 0 | 0
Financial assets, Ending Balance | 3 | 2 | 3 | 2
Collateralized loan obligations |  |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Financial assets, Beginning Balance | 0 | 1 | 0 | 1
Total realized/unrealized gains (losses) included in net earnings (loss) | 0 | (1) | 0 | (1)
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 0 | 0 | 0
Purchases and issuances | 0 | 0 | 0 | 0
Sales and settlements | 0 | 0 | 0 | 0
Transfer into Level 3 | 0 | 0 | 0 | 0
Transfer out of Level 3 | 0 | 0 | 0 | 0
Financial assets, Ending Balance | 0 | 0 | 0 | 0
Other asset-backed securities |  |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Financial assets, Beginning Balance | 284 | 340 | 296 | 351
Total realized/unrealized gains (losses) included in net earnings (loss) | 1 | 0 | 1 | (1)
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | (1) | 7 | 4 | 11
Purchases and issuances | 8 | 16 | 24 | 40
Sales and settlements | (15) | (5) | (48) | (17)
Transfer into Level 3 | 0 | 5 | 0 | 5
Transfer out of Level 3 | 0 | 0 | 0 | (26)
Financial assets, Ending Balance | 277 | 363 | 277 | 363
Corporate and other |  |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Financial assets, Beginning Balance | 461 | 411 | 470 | 380
Total realized/unrealized gains (losses) included in net earnings (loss) | 13 | 6 | 14 | 5
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 3 | 7 | 8 | 8
Purchases and issuances | 17 | 26 | 56 | 74
Sales and settlements | (82) | (5) | (130) | (17)
Transfer into Level 3 | 0 | 3 | 1 | 3
Transfer out of Level 3 | (12) | 0 | (19) | (5)
Financial assets, Ending Balance | 400 | 448 | 400 | 448
Trading fixed maturities |  |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Financial assets, Beginning Balance | 13 | 12 | 26 | 0
Total realized/unrealized gains (losses) included in net earnings (loss) | 1 | 1 | 2 | 1
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 0 | 0 | 0
Purchases and issuances | 0 | 12 | 0 | 24
Sales and settlements | 0 | 0 | (14) | 0
Transfer into Level 3 | 0 | 0 | 0 | 0
Transfer out of Level 3 | 0 | 0 | 0 | 0
Financial assets, Ending Balance | 14 | 25 | 14 | 25
Equity securities |  |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Financial assets, Beginning Balance | 286 | 602 | 292 | 485
Total realized/unrealized gains (losses) included in net earnings (loss) | 1 | 18 | 19 | 53
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 0 | 0 | 0
Purchases and issuances | 4 | 43 | 20 | 133
Sales and settlements | 0 | (43) | 0 | (51)
Transfer into Level 3 | 0 | 0 | 7 | 0
Transfer out of Level 3 | 0 | 0 | (47) | 0
Financial assets, Ending Balance | 291 | 620 | 291 | 620
Assets of MIE |  |  |  |
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] |  |  |  |
Financial assets, Beginning Balance | 11 | 12 | 10 | 9
Total realized/unrealized gains (losses) included in net earnings (loss) | (2) | (1) | (5) | (3)
Total realized/unrealized gains (losses) included in other comprehensive income (loss) | 0 | 0 | 0 | 0
Purchases and issuances | 5 | 0 | 9 | 5
Sales and settlements | 0 | 0 | 0 | 0
Transfer into Level 3 | 0 | 0 | 0 | 0
Transfer out of Level 3 | 0 | 0 | 0 | 0
Financial assets, Ending Balance | $ 14 | $ 11 | $ 14 | $ 11

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 102 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-102 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2G -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2G Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2G -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2G Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2G -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2G Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

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

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

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

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

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

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

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

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