XML 48 R35.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Segments of Operations - Revenues by segment and sub-segment (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2018 | Mar. 31, 2017
Segment Reporting Information [Line Items] |  |  |
Total premiums earned |  | $ 1,107 | $ 1,022
Net investment income |  | 495 | 435
Other income |  | 49 | 59
Revenues before realized gains (losses) |  | 1,712 | 1,573
Realized gains (losses) on securities |  | (93) | 3
Total revenues |  | 1,619 | 1,576
Property and Casualty Insurance |  |  |
Segment Reporting Information [Line Items] |  |  |
Total premiums earned |  | 1,107 | 1,022
Net investment income |  | 100 | 86
Other income | [1] | 2 | 16
Revenues before realized gains (losses) |  | 1,209 | 1,124
Annuity |  |  |
Segment Reporting Information [Line Items] |  |  |
Net investment income |  | 394 | 347
Other income |  | 26 | 27
Revenues before realized gains (losses) |  | 420 | 374
Other |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues before realized gains (losses) |  | 83 | 75
Specialty Property and transportation | Property and Casualty Insurance |  |  |
Segment Reporting Information [Line Items] |  |  |
Total premiums earned |  | 350 | 342
Specialty casualty | Property and Casualty Insurance |  |  |
Segment Reporting Information [Line Items] |  |  |
Total premiums earned |  | 579 | 508
Specialty financial | Property and Casualty Insurance |  |  |
Segment Reporting Information [Line Items] |  |  |
Total premiums earned |  | 149 | 147
Other specialty | Property and Casualty Insurance |  |  |
Segment Reporting Information [Line Items] |  |  |
Total premiums earned |  | $ 29 | $ 25
[1] | Includes income of $13 million (before noncontrolling interest) from the sale of a hotel in the first quarter of 2017.

X
- Definition Aggregate revenue (including insurance premiums, investment income and other income) recognized during the period before realized gains (losses) on securities and subsidiaries. + References No definition available. + Details
Name: | afg_RevenuesBeforeRealizedGainsLosses
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents the total realized gain (loss) included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(c)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27405-111563 + Details
Name: | us-gaap_MarketableSecuritiesRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(2)) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column G)) -URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574960-122915 + Details
Name: | us-gaap_NetInvestmentIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of revenue and income classified as other. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.4) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 + Details
Name: | us-gaap_OtherIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, after premiums ceded to other entities and premiums assumed by the entity, of property and casualty premiums earned. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.1) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (b),(c) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=84167274&loc=d3e27175-158546 + Details
Name: | us-gaap_PremiumsEarnedNetPropertyAndCasualty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_Revenues
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: | us-gaap_StatementBusinessSegmentsAxis=afg_PropertyAndCasualtyInsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=afg_AnnuityMember
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: |

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_SpecialtyOtherInsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |