Managed Investment Entities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Gains (losses) on change in fair value of assets/liabilities (a):
Assets	$ 17	[1]	$ 55	[1]
Liabilities	(25)	[1]	(84)	[1]
Management fees paid to AFG	4		4
CLO earnings (losses) attributable to (b):
AFG shareholders	11	[2]	5	[2]
Noncontrolling interests	$ (11)	[2]	$ (28)	[2]

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

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