Reserve for Property-Liability Insurance Claims and Claims Expense (Details) (Property-Liability, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property-Liability
Activity in the reserve for property-liability insurance claims and claims expense:
Balance at beginning of period	$ 21,288	$ 20,375	$ 19,468
Less reinsurance recoverables	4,010	2,588	2,072
Net balance at beginning of period	17,278	17,787	17,396
Esurance acquisition		(13)	425
Incurred claims and claims expense related to:
Current year	18,032	19,149	20,496
Prior years	(121)	(665)	(335)
Total incurred	17,911	18,484	20,161
Claims and claims expense paid related to:
Current year	11,658	12,545	13,893
Prior years	6,338	6,435	6,302
Total paid	17,996	18,980	20,195
Net balance at end of period	17,193	17,278	17,787
Plus reinsurance recoverables	4,664	4,010	2,588
Balance at end of period	$ 21,857	$ 21,288	$ 20,375