Fair Value of Financial Instruments-Derivative Instruments, Gain (Loss) by Hedging Relationship, Income Statement Location (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Total pre-tax gain (loss)	$ 15	$ 0	$ (19)	$ 3
Cost of Sales [Member] | Derivatives Designated as Hedges Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total pre-tax gain (loss)	4	(1)	1	1
Cost of Sales [Member] | Derivatives not Designated as Hedges Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total pre-tax gain (loss)	10	1	(9)	2
Other (costs) gains [Member] | Derivatives not Designated as Hedges Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total pre-tax gain (loss)	$ 1	$ 0	$ (11)	$ 0