Stockholders' Equity (Schedule of Components of Other Comprehensive Income (Loss), Net) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 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
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	0	0
Unrealized gain (loss) on marketable securities	0	1
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	28	70
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	0	(6)
Foreign currency translation	28	64
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Cash Flow Hedges Arising During Period, before Tax	(2)	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Cash Flow Hedges Arising During Period, Tax	0	0
Gain (loss) on cash flow hedges	(2)	0
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	5	0
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax	0	0
Pension and postretirement benefits	5	0
Other Comprehensive Income (Loss), before Tax	31	71
Income tax (provision) benefit	0	(6)
Total other comprehensive income (loss), net of tax	$ 31	$ 65