Noncurrent Other Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Other Liabilities, Noncurrent [Abstract]
Asset retirement obligations	$ 10	$ 20
Deferred proceeds	44	41
Deferred revenue	8	9
Environmental (Note 12)	52	50
Income taxes payable	6	6
Insurance	49	46
Other	56	43
Total	$ 225	$ 215