Valuation and Qualifying Accounts (Details) (Allowance for doubtful accounts [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Allowance for doubtful accounts [Member]
Valuation and Qualifying Accounts
Balance at beginning of year	$ 29		$ 38		$ 38
Net charges to income	32		26		13
Deductions and other	(7)	[1]	35	[1]	13	[1]
Balance at end of year	$ 54		$ 29		$ 38

[1] Primarily includes uncollectible accounts written off, net of recoveries, impact of acquisitions and divestitures and adjustments for foreign currency translation.