Stockholders' Equity (Schedule of Components of Other Comprehensive Income (Loss), Net) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Stockholders' Equity Note [Abstract]
Foreign currency translation gain (loss), gross amount	$ (12)	$ (72)	$ 1	$ (27)
Foreign currency translation gain (loss), income tax (provision) benefit	1	6	(5)	10
Foreign currency translation gain (loss), net	(11)	(66)	(4)	(17)
Gain (loss) on cash flow hedges, gross amount	(19)	6	(22)	4
Gain (loss) on cash flow hedges, income tax (provision) benefit	6	0	6	1
Gain (loss) on cash flow hedges, net	(13)	6	(16)	5
Pension and postretirement benefits gain (loss), gross amount	0	0	0	1
Pension and postretirement benefits gain (loss), income tax (provision) benefit	0	0	0	0
Pension and postretirement benefits gain (loss), net	0	0	0	1
Other Comprehensive Income (Loss), before Tax	(31)	(66)	(21)	(22)
Income tax (provision) benefit	7	6	1	11
Total other comprehensive income (loss), net of tax	$ (24)	$ (60)	$ (20)	$ (11)