Other Property and Equipment Net Gains (Losses) on Sales of Fixed Assets Table (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Property, Plant and Equipment [Line Items]
Net (gains) losses on sales of fixed assets	$ (1)	$ (86)	$ 3	$ (201)
Natural Gas Compressors [Member]
Property, Plant and Equipment [Line Items]
Net (gains) losses on sales of fixed assets	(1)	(75)	(1)	(195)
Gathering and Processing Equipment [Member]
Property, Plant and Equipment [Line Items]
Net (gains) losses on sales of fixed assets	1	(5)	1	8
Exploration and Production Equipment [Member]
Property, Plant and Equipment [Line Items]
Net (gains) losses on sales of fixed assets	0	0	0	(7)
Land and Building [Member]
Property, Plant and Equipment [Line Items]
Net (gains) losses on sales of fixed assets	(1)	(6)	0	(5)
Other Assets [Member]
Property, Plant and Equipment [Line Items]
Net (gains) losses on sales of fixed assets	$ 0	$ 0	$ 3	$ (2)