Stockholders' Equity (Schedule of Adjustments to Accumulated Other Comprehensive Income (Loss), Net) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2018	$ (247)
Other comprehensive income (loss) before reclassifications	12
Amounts reclassified from accumulated other comprehensive income (loss)	(2)
Income tax (provision) benefit	(6)	$ 5
As of March 31, 2019	(243)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2018	(236)
Other comprehensive income (loss) before reclassifications	13
Amounts reclassified from accumulated other comprehensive income (loss)	0
Income tax (provision) benefit	(6)
As of March 31, 2019	(229)
Gain (Loss) from Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2018	(8)
Other comprehensive income (loss) before reclassifications	(1)
Amounts reclassified from accumulated other comprehensive income (loss)	(2)
Income tax (provision) benefit	0
As of March 31, 2019	(11)
Pension and Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2018	(3)
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, 2019	$ (3)