Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Tax provision on fair market value adjustment on cash flow hedges	$ 1	$ 0	$ 2	$ 0
Tax provision on reclassification adjustment for net realized losses on cash flow hedges	$ 1	$ 1	$ 2	$ 2