SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS 2 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Valuation And Qualifying Accounts Deferred Tax Assets Disclosure [Line Items]
Balance at end of period,	$ 598	$ 591
Deferred Tax Assets Valuation Allowance [Member]
Valuation And Qualifying Accounts Deferred Tax Assets Disclosure [Line Items]
Balance at beginning of period,	591	636	578
Additions charged to income tax expense	72	109	129
Reductions credited to income tax expense	(54)	(152)	(90)
Additions (reductions) to equity	12	(13)	(17)
Additions (reductions) due to capital loss carryforwards	14	(5)	(1)
Reductions due to expiring NOLs	(2)	(8)	(7)
Additions charged (reductions credited) to goodwill	(35)	24	44
Balance at end of period,	598	591	636
Allowance for Doubtful Accounts [Member]
Valuation And Qualifying Accounts Deferred Tax Assets Disclosure [Line Items]
Additions charged to income tax expense	$ 100	$ 79	$ 145