Noncurrent Other Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Other Liabilities, Noncurrent [Abstract]
Asset retirement obligations	$ 22	$ 26
Deferred proceeds	43	43
Deferred revenue	10	13
Environmental (Note 10)	54	61
Income taxes payable	6	7
Insurance	46	50
Other	40	47
Total	$ 221	$ 247