Condensed Financial Information of Parent Company (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Assets:
Cash and cash equivalents	$ 1,343		$ 1,639		$ 1,705	$ 1,324
Total assets	47,535		42,087		39,171
Liabilities and Equity:
Long-term debt	1,061		913
Shareholders’ equity	4,879		4,599
Total liabilities and equity	47,535		42,087
AFG [Member]
Assets:
Cash and cash equivalents	292		523		279	415
Investment in securities	58		53
Investment in subsidiaries	5,638	[1]	5,041	[1]
Other investments	2		2
Other assets	103		108
Total assets	6,093		5,727
Liabilities and Equity:
Long-term debt	990		840
Other liabilities	224		288
Shareholders’ equity	4,879		4,599
Total liabilities and equity	$ 6,093		$ 5,727

[1] Investment in subsidiaries includes intercompany receivables and payables.