Managed Investment Entities (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Gains (losses) on change in fair value of assets/liabilities (a):
Assets	$ 95	[1]	$ (33)	[1]	$ 150	[1]
Liabilities	(189)	[1]	0	[1]	(220)	[1]
Management fees paid to AFG	18		19		15
CLO earnings (losses) attributable to (b):
AFG shareholders	31	[2]	6	[2]	17	[2]
Noncontrolling interests	$ (98)	[2]	$ (24)	[2]	$ (64)	[2]

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

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