Segments of Operations (Details 2) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes		$ 745	$ 574	$ 472
Realized gains (losses) on securities		(19)	52	221
Realized losses on subsidiaries		(161)	0	(4)
Earnings before income taxes		565	626	689
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		225	212	145
Investment and other income, net	[1]	351	244	230
Earnings before realized gains (losses) and income taxes		576	456	375
Annuity [Member]
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	[2]	331	328	323
Run-off Long-term Care and Life [Member]
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	[3]	14	(10)	(10)
Other [Member]
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	[4]	(176)	(200)	(216)
Specialty Property and transportation [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		48	21	12
Specialty casualty [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		146	136	102
Specialty financial [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		87	64	67
Specialty Other [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		14	16	25
Other Lines [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	[5]	$ (70)	$ (25)	$ (61)

[1] Includes pretax income of $51 million (before noncontrolling interest) from the sale of the Le Pavillon Hotel in the second quarter of 2015 and $15 million from the sale of an apartment property in the fourth quarter of 2015.

[2] Includes a $5 million charge in the second quarter of 2013 to cover expected assessments from state guaranty funds related to insolvency and liquidation of an unaffiliated life insurance company.

[3] AFG sold substantially all of its run-off long-term care insurance business in December 2015.

[4] Primarily holding company expenses, including a $4 million loss on retirement of debt in the third quarter of 2015 and special charges to increase A&E reserves related to AFG’s former railroad and manufacturing operations ($12 million in 2015, $6 million in 2014 and $22 million in 2013) and losses of managed investment entities attributable to noncontrolling interests ($51 million in 2014 and $26 million in 2013). Following the adoption of new guidance in the first quarter of 2015, there are no longer earnings (losses) of managed investment entities that are attributable to noncontrolling interests. See Note A — “Accounting Policies — Managed Investment Entities.”

[5] Includes special charges to increase asbestos and environmental (“A&E”) reserves of $67 million, $24 million and $54 million in 2015, 2014 and 2013, respectively.