Managed Investment Entities (Details Textual) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013 collateralizedloanobligations	Dec. 31, 2012	Jun. 30, 2013 Variable Interest Entity, Primary Beneficiary [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member]	Apr. 30, 2013 New CLO Formed in April 2013 [Member]	Jun. 30, 2013 Senior Debt Obligations [Member]
Variable Interest Entity [Line Items]
Aggregate fair value of investment in collateralized loan obligations			$ 336	$ 257
Aggregate fair value of investment in collateralized loan obligations, most subordinate debt tranches			105
Face amount of liabilities					417
Face amount of liabilities purchased by subsidiaries of AFG					23
Purchased CLO senior debt, face amount						94
Purchased CLO senior debt, purchase price						89
Managed Investment Entities (Textual) [Abstract]
Percentage of investment of most subordinate debt tranche, Minimum	7.50%
Percentage of investment of most subordinate debt tranche, Maximum	51.20%
Number of collateralized loan obligation entities	10
Difference between aggregate unpaid principal balance and fair value of CLOs' fixed maturity investments	26	29
Difference between aggregate unpaid principal balance and fair value of CLOs' debt	88	123
Carrying amount of CLO loans in default	1	5
Aggregate unpaid principal balance of CLO loans in default	$ 2	$ 12