Derivative Instruments and Hedging Activities - Pre-tax Gains (Losses) (Details) - Not designated as a hedge - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative instruments and hedging activities
Total gain (loss)	$ (3)	$ 1	$ (3)	$ 3
Metals contracts | Cost of sales
Derivative instruments and hedging activities
Total gain (loss)	0	2	0	4
Interest rate swaps
Derivative instruments and hedging activities
Total gain (loss)	$ (3)	$ (1)	$ (3)	$ (1)