CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 247	$ 240	$ 466	$ 447
Other comprehensive income (loss):
Foreign currency translation adjustments	3	7	25	(19)
Derivative instrument adjustments, net of tax	1	(2)	(4)	7
Unrealized loss on available-for-sale securities, net of tax	(1)	(1)	0	(2)
Reclassification of losses (gains), net of tax	1	(2)	2	(4)
Total other comprehensive income (loss), net of tax	4	2	23	(18)
Comprehensive income	$ 251	$ 242	$ 489	$ 429