Income Taxes (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes
Undistributed earnings of foreign subsidiaries	$ 1,978
Unrecognized tax benefits that affect our effective tax rate if recognized	206
Reconciliation of unrecognized tax benefits
Unrecognized tax benefits balance at January 1	154	132	139
Gross increase for tax positions of prior years	3	4	0
Gross decrease for tax positions of prior years	0	0	0
Gross increase for tax positions of current year	59	65	21
Settlements	(8)	0	(16)
Lapse of statute of limitations	(1)	(47)	(12)
Unrecognized tax benefits balance at December 31	207	154	132
Income tax liabilities, non-current	197	146
Accrued interest and penalties related to uncertain tax positions	11	12
Interest expense related to uncertain tax positions	0	1	3
Reduction in previously unrecognized tax benefits within next twelve months	$ 10