Noncurrent Other Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Other Liabilities, Noncurrent [Abstract]
Asset retirement obligations	$ 29	$ 28
Deferred proceeds	43	47
Deferred revenue	18	21
Derivatives (Note 14)	0	10
Environmental (Note 10)	61	63
Income taxes payable	12	13
Insurance	52	51
Other	47	50
Total	$ 262	$ 283