Accumulated Other Comprehensive Income/(Loss) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Cumulative Translation Adjustment Summary [Roll Forward]
Beginning Balance	$ (890,000,000)	$ (607,000,000)
Net gain/(loss) on Foreign Currency Translation	90,000,000	172,000,000
Other Comprehensive Income (Loss), Net of Tax	90,000,000	172,000,000
Ending Balance	(800,000,000)	(435,000,000)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(800,000,000)	(435,000,000)	$ (890,000,000)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Net gain/(loss) on foreign currency translation, tax adjustment	0	0
Accumulated Other Comprehensive Income (Loss) [Member]
Cumulative Translation Adjustment Summary [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	$ 90,000,000	$ 172,000,000