Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Long-term Purchase Commitment [Line Items]
Purchase commitment, amount to be paid in 2020	$ 9
Purchase commitment, amount to be paid in 2021	9
Inventories
Long-term Purchase Commitment [Line Items]
Purchase commitment	$ 212
Purchase commitment, period (in years)	5 years
Purchase commitment, purchases made	$ 4	$ 11
Purchase commitment, amount to be paid in 2017	4
Purchase commitment, amount to be paid in 2018	61
Purchase commitment, amount to be paid in 2019	$ 129