Condensed Financial Information of Parent Company - Condensed Statement of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Other Comprehensive Income [Abstract]
Net earnings attributable to shareholders	$ 385	$ 109	$ 54	$ 101	$ 129	$ 63	$ 141	$ 19	$ 649	$ 352	$ 452
Comprehensive income (loss) attributable to shareholders									711	(71)	619
AFG
Statement of Other Comprehensive Income [Abstract]
Net earnings attributable to shareholders									649	352	452
Other comprehensive income (loss), net of tax									62	(423)	167
Comprehensive income (loss) attributable to shareholders									$ 711	$ (71)	$ 619