Managed Investment Entities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Gains (losses) on change in fair value of assets/liabilities (a):
Assets	$ (2)	[1]	$ 39	[1]	$ 1	[1]	$ 92	[1]
Liabilities	17	[1]	(52)	[1]	(22)	[1]	(155)	[1]
Management fees paid to AFG	4		6		12		14
CLO earnings (losses) attributable to (b):
AFG shareholders	9	[2]	11	[2]	27	[2]	21	[2]
Noncontrolling interests	$ 12	[2]	$ (18)	[2]	$ (30)	[2]	$ (64)	[2]

[1] Included in Revenues in AFG’s Statement of Earnings.

[2] Included in Earnings before income taxes in AFG’s Statement of Earnings.