SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for Doubtful Accounts [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period,	$ 272	$ 230	$ 182
Provision Charged to Income	79	145	176
Deductions from reserves	(112)	(111)	(134)
Acquisitions	14	8	6
Balance at end of period,	253	272	230
Deferred Tax Assets Valuation Allowance [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Provision Charged to Income	$ 109	$ 129	$ 142