Stockholders' Equity (Schedule of Components of Other Comprehensive Income (Loss), Net) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss), net [Line Items]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	$ 0	$ (1)	$ 1	$ 0
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	0	0	0	0
Unrealized gain (loss) on marketable securities	0	(1)	1	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	44	(2)	143	51
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	(2)	(6)	5	(13)
Foreign currency translation	42	(8)	148	38
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Cash Flow Hedges Arising During Period, before Tax	0	0	(1)	1
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Cash Flow Hedges Arising During Period, Tax	0	0	0	0
Gain (loss) on cash flow hedges	0	0	(1)	1
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	(1)	0	4	(1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	0	0	0	0
Pension and postretirement benefits	(1)	0	4	(1)
Other Comprehensive Income (Loss), before Tax	43	(3)	147	51
Income tax (provision) benefit	(2)	(6)	5	(13)
Total other comprehensive income (loss), net of tax	$ 41	$ (9)	$ 152	$ 38