Restructuring Charges/Other - Components of Restructuring Charges and Other (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Restructuring Cost And Reserve [Line Items]
Restructuring charges		$ 0	$ (4)	$ (1)	[1]	$ 22
Gains on sales of assets		(1)	(2)	(1)		(39)
Other		0	2	(1)		2
Restructuring charges/other		(1)	(4)	(3)		(15)
2013 Actions
Restructuring Cost And Reserve [Line Items]
Restructuring charges	[1]	0	(4)	(1)		28
Prior Actions
Restructuring Cost And Reserve [Line Items]
Restructuring charges	[1]	$ 0	$ 0	$ 0		$ (6)

[1] Includes changes in estimates.