Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), balance at beginning of period	$ (303)	$ 68
Other comprehensive income (loss) before reclassifications	(315)	(363)
Amounts reclassified from accumulated other comprehensive income (loss)	(15)	(8)
Accumulated other comprehensive income (loss), balance at end of period	(633)	(303)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), balance at beginning of period	(304)	67
Other comprehensive income (loss) before reclassifications	(326)	(371)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Accumulated other comprehensive income (loss), balance at end of period	(630)	(304)
Unrealized gain (loss) on available-for- sale securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), balance at beginning of period	1	1
Other comprehensive income (loss) before reclassifications	1	0
Amounts reclassified from accumulated other comprehensive income (loss)	(1)	0
Accumulated other comprehensive income (loss), balance at end of period	1	1
Unrealized gain (loss) on forward contracts
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), balance at beginning of period	0	0
Other comprehensive income (loss) before reclassifications	10	8
Amounts reclassified from accumulated other comprehensive income (loss)	(14)	(8)
Accumulated other comprehensive income (loss), balance at end of period	$ (4)	$ 0