Condensed Financial Information of Parent Company (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Other Comprehensive Income [Abstract]
Net earnings attributable to shareholders	$ 127	$ 116	$ 106	$ 103	$ 158	$ 83	$ 110	$ 120	$ 452	$ 471	$ 488
Other comprehensive income (loss), net of tax									167	(271)	252
Comprehensive income attributable to shareholders									619	200	740
AFG [Member]
Statement of Other Comprehensive Income [Abstract]
Net earnings attributable to shareholders									452	471	488
Other comprehensive income (loss), net of tax									167	(271)	252
Comprehensive income attributable to shareholders									$ 619	$ 200	$ 740