Derivative Instruments - Designation (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Derivatives, Fair Value
Total asset derivatives	$ 9	$ 14	$ 8
Total liability derivatives	3	5	5
Derivatives designated as hedging instruments | Commodity forward contracts | Receivables.
Derivatives, Fair Value
Total asset derivatives	3
Derivatives not designated as hedging instruments | Commodity futures contracts | Other liabilities (current)
Derivatives, Fair Value
Total liability derivatives		3
Derivatives not designated as hedging instruments | Forward exchange derivative contracts. | Receivables.
Derivatives, Fair Value
Total asset derivatives	6	14	8
Derivatives not designated as hedging instruments | Forward exchange derivative contracts. | Other liabilities (current)
Derivatives, Fair Value
Total liability derivatives	$ 3	$ 2	$ 5