Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cumulative Translation Adjustment Summary [Roll Forward]
Beginning balance	$ 600	$ 821	$ 1,052
Net gain/(loss) on foreign currency translation	143	(161)	(106)
Reclassifications to net income	0	(60)	0
Ending balance	743	600	821
Total AOCI ending balance at December 31	743	600	821
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Net gain/(loss) on foreign currency translation, tax adjustment	0	0	0
Reclassifications to net income, tax adjustment	0	0	0
Total other comprehensive income/(loss), net of tax	143	(221)	(106)
Out of Period Adjustment [Member]
Cumulative Translation Adjustment Summary [Roll Forward]
Net gain/(loss) on foreign currency translation	0	0	(125)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Net gain/(loss) on foreign currency translation, tax adjustment			0
Accumulated Other Comprehensive Income (Loss) [Member]
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Total other comprehensive income/(loss), net of tax	$ 143	$ (221)	$ (231)