Income Taxes (Unrecognized Income Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Tax Expense (Benefit) [Abstract]
Balance at January 1	$ 568	$ 570	$ 438
Gross increases for tax positions of prior years	17	67	139
Gross decreases for tax positions of prior years	(60)	(89)	(77)
Gross increases for tax positions of the current year	55	54	113
Settlements	(15)	(36)	(39)
Lapse of statute of limitations	(4)	0	(10)
Currency	(3)	2	6
Balance at December 31	$ 558	$ 568	$ 570