Noncurrent Other Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Other Liabilities, Noncurrent [Abstract]
Asset retirement obligations	$ 7	$ 7
Deferred proceeds	48	47
Deferred revenue	6	6
Environmental (Note 12)	57	59
Income taxes payable	0	197
Insurance	43	43
Other	56	54
Total	$ 217	$ 413