XML 49 R37.htm IDEA: XBRL DOCUMENT
v3.25.1

Segments of Operations - Earnings before income taxes by segment and sub-segment (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2025 | Mar. 31, 2024
Segment Reporting Information [Line Items] |  |
Earnings before realized gains and income taxes | $ 194 | $ 290
Realized gains on securities | 3 | 14
Earnings before income taxes | 197 | 304
Operating segments | Property and Casualty Insurance |  |
Segment Reporting Information [Line Items] |  |
Property and casualty insurance underwriting | 94 | 153
Investment and other income, net | 152 | 187
Earnings before realized gains and income taxes | 246 | 340
Operating segments | Property and Casualty Insurance | Property and transportation |  |
Segment Reporting Information [Line Items] |  |
Property and casualty insurance underwriting | 37 | 60
Operating segments | Property and Casualty Insurance | Specialty casualty |  |
Segment Reporting Information [Line Items] |  |
Property and casualty insurance underwriting | 20 | 61
Operating segments | Property and Casualty Insurance | Specialty financial |  |
Segment Reporting Information [Line Items] |  |
Property and casualty insurance underwriting | 37 | 33
Operating segments | Property and Casualty Insurance | Other lines |  |
Segment Reporting Information [Line Items] |  |
Property and casualty insurance underwriting | 0 | (1)
Operating segments | Other |  |
Segment Reporting Information [Line Items] |  |
Earnings before realized gains and income taxes | $ (52) | $ (50)

X
- Definition Net investment income plus other income less other expenses. + References No definition available. + Details
Name: | afg_InvestmentAndOtherIncomeNet
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The net result for the period of deducting operating expenses from operating revenues (excluding realized gains (losses) on securities and subsidiaries) before income taxes. + References No definition available. + Details
Name: | afg_OperatingIncomeLossBeforeRealizedGainsLossesAndIncomeTaxes
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Underwriting income (loss) for the property and casualty insurance segment, which is calculated as premiums earned less losses and loss adjustment expenses less commissions and other underwriting expenses. + References No definition available. + Details
Name: | afg_PropertyAndCasualtyInsuranceUnderwritingIncomeLoss
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of realized gain (loss) on investment in debt and equity securities. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(9)(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(7)(c)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 6 -Subparagraph (SX 210.12-14(Column C)(Footnote 4)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-6 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 6 -Subparagraph (SX 210.12-14(Column C)(Footnote 6)(e)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-6 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 6 -Subparagraph (SX 210.12-14(Column C)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-6 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-07(7)(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-07(7)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1 + Details
Name: | us-gaap_DebtAndEquitySecuritiesRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The net result for the period of deducting operating expenses from operating revenues. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-22 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 32 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-32 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 30 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-30 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 270 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482964/270-10-50-1 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 32 -Subparagraph (ee) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-32 Reference 6: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 32 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-32 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 31 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-31 + Details
Name: | us-gaap_OperatingIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=afg_PropertyAndCasualtyInsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsegmentsAxis=afg_SpecialtyPropertyAndTransportationInsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsegmentsAxis=afg_SpecialtyCasualtyInsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsegmentsAxis=afg_SpecialtyFinancialInsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsegmentsAxis=afg_OtherLinesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=us-gaap_CorporateAndOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |