Impairments Impairments - Fixed Assets and Other Table (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Property, Plant and Equipment [Line Items]
Impairments of fixed assets and other	$ 6	$ 84	$ 44	$ 88
Compressor [Member]
Property, Plant and Equipment [Line Items]
Impairments of fixed assets and other	0	21	20	21
Buildings and land [Member]
Property, Plant and Equipment [Line Items]
Impairments of fixed assets and other	0	0	7	0
Other [Member]
Property, Plant and Equipment [Line Items]
Impairments of fixed assets and other	$ 6	$ 63	$ 17	$ 67