Stockholders' Equity (Schedule of Adjustments to Accumulated Other Comprehensive Income (Loss), Net) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2017	$ (177)
Other comprehensive income (loss) before reclassifications	44
Amounts reclassified from accumulated other comprehensive income (loss)	0
Income tax (provision) benefit	5	$ 0
As of March 31, 2018	(128)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2017	(176)
Other comprehensive income (loss) before reclassifications	45
Amounts reclassified from accumulated other comprehensive income (loss)	0
Income tax (provision) benefit	4
As of March 31, 2018	(127)
Gain (Loss) from Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2017	2
Other comprehensive income (loss) before reclassifications	(2)
Amounts reclassified from accumulated other comprehensive income (loss)	0
Income tax (provision) benefit	1
As of March 31, 2018	1
Pension and Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2017	(3)
Other comprehensive income (loss) before reclassifications	1
Amounts reclassified from accumulated other comprehensive income (loss)	0
Income tax (provision) benefit	0
As of March 31, 2018	$ (2)