Noncurrent Other Liabilities (Schedule of Noncurrent Other Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Other Liabilities, Noncurrent [Abstract]
Asset retirement obligations	$ 20	$ 26
Deferred proceeds	41	43
Deferred revenue	9	13
Environmental (Note 16)	50	61
Income taxes payable	6	7
Insurance	46	50
Other	43	47
Total	$ 215	$ 247