Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), balance as of January 1			$ 24	$ (233)
Other comprehensive income (loss), before reclassifications, net of tax			4	(27)
Less: Reclassification from accumulated other comprehensive income (loss), net of tax			14	(5)
Net other comprehensive income (loss)	(4)	(31)	(10)	(22)
Accumulated other comprehensive income (loss), balance as of June 30	14	(255)	14	(255)
Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), balance as of January 1			35	32
Other comprehensive income (loss), before reclassifications, net of tax			2	2
Less: Reclassification from accumulated other comprehensive income (loss), net of tax			3	0
Net other comprehensive income (loss)			(1)	2
Accumulated other comprehensive income (loss), balance as of June 30	34	34	34	34
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), balance as of January 1			(32)	(303)
Other comprehensive income (loss), before reclassifications, net of tax			(9)	(12)
Less: Reclassification from accumulated other comprehensive income (loss), net of tax			6	(5)
Net other comprehensive income (loss)			(15)	(7)
Accumulated other comprehensive income (loss), balance as of June 30	(47)	(310)	(47)	(310)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), balance as of January 1			21	38
Other comprehensive income (loss), before reclassifications, net of tax			11	(17)
Less: Reclassification from accumulated other comprehensive income (loss), net of tax			5	0
Net other comprehensive income (loss)			6	(17)
Accumulated other comprehensive income (loss), balance as of June 30	$ 27	$ 21	$ 27	$ 21