Segments of Operations (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended						3 Months Ended	12 Months Ended	3 Months Ended			12 Months Ended			3 Months Ended
	Dec. 31, 2013 segment		Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2012 Run-off Long-term Care and Life [Member]	Dec. 31, 2013 Run-off Long-term Care and Life [Member]	Sep. 30, 2013 Other [Member]	Sep. 30, 2012 Other [Member]	Jun. 30, 2011 Other [Member]	Dec. 31, 2013 Other [Member]	Dec. 31, 2012 Other [Member]	Dec. 31, 2011 Other [Member]	Sep. 30, 2013 Other Lines [Member]	Sep. 30, 2012 Other Lines [Member]	Jun. 30, 2011 Other Lines [Member]	Jun. 30, 2013 Insurance-related Assessments [Member] Annuity [Member]
Segments of Operations (Textual) [Abstract]
Number of segments	5
Revenue derived from sales of property and casualty insurance outside of the United States	5.00%		5.00%		5.00%
Special charges to increase asbestos and environmental reserves									$ 22	$ 2	$ 9				$ 54	$ 31	$ 50
Charge for guaranty fund assessments for the insolvency and liquidation of an unaffiliated life insurance company																		5
Loss recognition charge on closed block of long-term care insurance							153	0
Earnings (losses) of managed investment entities attributable to noncontrolling interests	(26)	[1]	(98)	[1]	(24)	[1]						(26)	(98)	(24)
Loss on retirement of debt													(8)
Charge for a labor matter related to former operations													$ 15

[1] Included in Earnings before income taxes in AFG’s Statement of Earnings.