SCHEDULE VI - SUPPLEMENTARY INFORMATION CONCERNING CONSOLIDATED PROPERTY-CASUALTY INSURANCE OPERATIONS (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
SCHEDULE VI - SUPPLEMENTARY INFORMATION CONCERNING CONSOLIDATED PROPERTY-CASUALTY INSURANCE OPERATIONS
Deferred policy acquisition costs	$ 1,396	$ 1,348	$ 1,321
Reserves for insurance claims and claims expense	21,288	20,375	19,468
Unearned premiums	10,345	10,023	9,761
Earned premiums	26,737	25,942	25,957
Net investment income	1,326	1,201	1,189
Claims and claims adjustment expense incurred:
Current year	19,149	20,496	19,110
Prior years	(665)	(335)	(159)
Amortization of deferred policy acquisition costs	3,483	3,477	3,517
Paid claims and claims adjustment expense	18,980	20,195	18,583
Premiums written	$ 27,027	$ 25,980	$ 25,907