Reinsurance (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property-liability insurance premiums earned
Direct	$ 31,547	$ 30,654	$ 29,969
Assumed	131	88	59
Ceded	(1,708)	(1,764)	(1,848)
Property-liability insurance premiums earned, net of reinsurance	29,970	28,978	28,180
Life and annuity premiums and contract charges
Life and annuity premiums and contract charges, net of reinsurance	2,352	2,241	2,238
Property-liability insurance premiums earned
Property-liability insurance premiums written
Direct	29,241	28,103	27,066
Assumed	52	35	22
Ceded	(1,129)	(1,111)	(1,108)
Property-liability insurance premiums written, net of reinsurance	28,164	27,027	25,980
Property-liability insurance premiums earned
Direct	28,638	27,794	27,016
Assumed	49	33	24
Ceded	(1,069)	(1,090)	(1,098)
Property-liability insurance premiums earned, net of reinsurance	27,618	26,737	25,942
Life and annuity premiums and contract charges
Life and annuity premiums and contract charges
Direct	2,909	2,860	2,953
Assumed	82	55	35
Ceded	(639)	(674)	(750)
Life and annuity premiums and contract charges, net of reinsurance	$ 2,352	$ 2,241	$ 2,238