Stockholders' Equity (Schedule of Adjustments to Accumulated 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]
As of December 31, 2016	$ (358)
Other comprehensive income (loss) before reclassifications	32
Amounts reclassified from accumulated other comprehensive income (loss)	(1)
Income tax (provision) benefit	0	$ (6)
As of March 31, 2017	(327)
Unrealized Gain (Loss) on Marketable Securities [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2016	1
Other comprehensive income (loss) before reclassifications	0
Amounts reclassified from accumulated other comprehensive income (loss)	0
Income tax (provision) benefit	0
As of March 31, 2017	1
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2016	(350)
Other comprehensive income (loss) before reclassifications	28
Amounts reclassified from accumulated other comprehensive income (loss)	0
Income tax (provision) benefit	0
As of March 31, 2017	(322)
Gain (Loss) from Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2016	3
Other comprehensive income (loss) before reclassifications	(1)
Amounts reclassified from accumulated other comprehensive income (loss)	(1)
Income tax (provision) benefit	0
As of March 31, 2017	1
Pension and Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2016	(12)
Other comprehensive income (loss) before reclassifications	5
Amounts reclassified from accumulated other comprehensive income (loss)	0
Income tax (provision) benefit	0
As of March 31, 2017	$ (7)