Stockholders' Equity (Schedule of Adjustments to Accumulated Other Comprehensive Income (Loss), Net) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
As of December 31, 2012				$ (89)	[1]
Other comprehensive income, before reclassifications				(4)
Amounts reclassified from accumulated other comprehensive income				6
Income tax (provision) benefit	(3)	(1)	[1]	(4)		(5)	[1]
As of June 30, 2013	(91)			(91)
Unrealized Gain (Loss) on Marketable Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
As of December 31, 2012				(1)
Other comprehensive income, before reclassifications				0
Amounts reclassified from accumulated other comprehensive income				0
Income tax (provision) benefit				0
As of June 30, 2013	(1)			(1)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
As of December 31, 2012				(23)
Other comprehensive income, before reclassifications				(3)
Amounts reclassified from accumulated other comprehensive income				0
Income tax (provision) benefit				(2)
As of June 30, 2013	(28)			(28)
Gain (Loss) on Interest Rate Swaps [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
As of December 31, 2012				(50)
Other comprehensive income, before reclassifications				(1)
Amounts reclassified from accumulated other comprehensive income				6
Income tax (provision) benefit				(2)
As of June 30, 2013	(47)			(47)
Pension and Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
As of December 31, 2012				15	[1]
Other comprehensive income, before reclassifications				0
Amounts reclassified from accumulated other comprehensive income				0
Income tax (provision) benefit				0
As of June 30, 2013	$ 15			$ 15

[1] As Adjusted (Note 1)