Condensed Consolidated Statements Of Comprehensive Income Statement - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 369	$ 202
Other comprehensive income, net of tax (Note 10)
Unrealized gain (loss) on cash flow hedges, net of income tax expense (benefit) of $1 and $(3)	1	(4)
Foreign currency translation adjustment, net of income tax (benefit) expense of $(1) and $4	59	94
Other comprehensive income, net of tax	60	90
Comprehensive income	$ 429	$ 292