XML 71 R58.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Deferred Policy Acquisition Costs - Narrative (Details) - USD ($) $ in Millions | Sep. 30, 2017 | Dec. 31, 2016
--- | --- | ---
Deferred Policy Acquisition Costs Disclosures [Abstract] |  |
Accumulated amortization of present value of future profits | $ 140 | $ 134

X
- Definition The cumulative amount of amortization of present value of future profits that has been recognized in the Income Statement. + References No definition available. + Details
Name: | afg_AccumulatedAmortizationOfPresentValueOfFutureProfits
Namespace Prefix: | afg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DeferredPolicyAcquisitionCostsDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration