Stockholders' Equity (Schedule of Adjustments to Accumulated Other Comprehensive Income (Loss), Net) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2018			$ (247)
Other comprehensive income (loss) before reclassifications			(17)
Amounts reclassified from accumulated other comprehensive income (loss)			(4)
Income tax (provision) benefit	$ 7	$ 6	1	$ 11
As of June 30, 2019	(267)		(267)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2018			(236)
Other comprehensive income (loss) before reclassifications			1
Amounts reclassified from accumulated other comprehensive income (loss)			0
Income tax (provision) benefit			(5)
As of June 30, 2019	(240)		(240)
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			(18)
Amounts reclassified from accumulated other comprehensive income (loss)			(4)
Income tax (provision) benefit			6
As of June 30, 2019	(24)		(24)
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 June 30, 2019	$ (3)		$ (3)