CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 447	$ 500
Other comprehensive income (loss):
Foreign currency translation adjustment, net of tax	2	1
Unrealized gains (losses) on forward contracts designated as hedges, net of tax	2	(12)
Unrealized gains (losses) on investments, net of tax	(5)	(3)
Total other comprehensive income (loss)	(1)	(14)
Comprehensive income	$ 446	$ 486