Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			$ (338)	$ 24
Other comprehensive income (loss) before reclassifications, net of tax			(42)	4
Less: Amounts reclassified from AOCI, net of tax			(8)	14
Other comprehensive loss, net of tax	$ (8)	$ (4)	(34)	(10)
Ending balance	(372)	14	(372)	14
Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			16	35
Other comprehensive income (loss) before reclassifications, net of tax			(1)	2
Less: Amounts reclassified from AOCI, net of tax			(5)	3
Other comprehensive loss, net of tax			4	(1)
Ending balance	20	34	20	34
Defined Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(302)	(32)
Other comprehensive income (loss) before reclassifications, net of tax			(2)	(9)
Less: Amounts reclassified from AOCI, net of tax			(3)	6
Other comprehensive loss, net of tax			1	(15)
Ending balance	(301)	(47)	(301)	(47)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(52)	21
Other comprehensive income (loss) before reclassifications, net of tax			(39)	11
Less: Amounts reclassified from AOCI, net of tax			0	5
Other comprehensive loss, net of tax			(39)	6
Ending balance	$ (91)	$ 27	$ (91)	$ 27