CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 70	$ 210	$ 536	$ 657
Other comprehensive income (loss):
Foreign currency translation adjustments	2	(28)	27	(47)
Derivative instrument adjustments, net of tax	1	2	(3)	9
Unrealized loss on available-for-sale securities, net of tax	0	(3)	0	(5)
Reclassification of losses (gains), net of tax	1	(3)	3	(7)
Total other comprehensive income (loss), net of tax	4	(32)	27	(50)
Comprehensive income	$ 74	$ 178	$ 563	$ 607