Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income tax provision on fair market value adjustment on cash flow hedges	$ (2)	$ 1	$ (2)	$ 2
Cost of Services
Income (benefit) expense on reclassification adjustment for net realized gain on cash flow hedges	0	0	(1)	0
Interest Expense
Income (benefit) expense on reclassification adjustment for net realized gain on cash flow hedges	$ 0	$ 1	$ 1	$ 2