Stockholders' Equity (Schedule of Adjustments to Accumulated Other Comprehensive Income (Loss), Net) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2016			$ (358)
Other comprehensive income (loss) before reclassifications			107
Amounts reclassified from accumulated other comprehensive income (loss)			(3)
Income tax (provision) benefit	$ 7	$ (1)	7	$ (7)
As of June 30, 2017	(247)		(247)
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			1
Amounts reclassified from accumulated other comprehensive income (loss)			0
Income tax (provision) benefit			0
As of June 30, 2017	2		2
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss), net [Line Items]
As of December 31, 2016			(350)
Other comprehensive income (loss) before reclassifications			99
Amounts reclassified from accumulated other comprehensive income (loss)			0
Income tax (provision) benefit			7
As of June 30, 2017	(244)		(244)
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)			(2)
Income tax (provision) benefit			0
As of June 30, 2017	2		2
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			6
Amounts reclassified from accumulated other comprehensive income (loss)			(1)
Income tax (provision) benefit			0
As of June 30, 2017	$ (7)		$ (7)