Noncurrent Other Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Other Liabilities, Noncurrent [Abstract]
Asset retirement obligations	$ 30	$ 28
Deferred proceeds	43	47
Deferred revenue	16	21
Derivatives (Note 14)	0	10
Environmental (Note 10)	60	63
Income taxes payable	11	13
Insurance	54	51
Other	50	50
Total	$ 264	$ 283