Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Cumulative Translation Adjustment Summary [Roll Forward]
Beginning balance			$ 743	$ 600
Net gain/(loss) on foreign currency translation			(238)	(44)
Ending balance	505	556	505	556
Total AOCI ending balance at June 30	505	556	505	556	743
Total other comprehensive income/(loss), net of tax	(51)	(252)	(238)	(44)
Accumulated Other Comprehensive Income (Loss) [Member]
Cumulative Translation Adjustment Summary [Roll Forward]
Total other comprehensive income/(loss), net of tax			$ (238)	$ (44)