Other Property and Equipment - Narrative (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Property, Plant and Equipment [Line Items]
Net gains (losses) on sales of fixed assets	$ (93)	$ (109)	$ (115)	$ (158)
Reclassification from held for sale to held for use	116		116
Compressor [Member]
Property, Plant and Equipment [Line Items]
Equipment, Number of Units	337		102
Proceeds from Sale of Property, Plant, and Equipment	362
Net gains (losses) on sales of fixed assets	(93)
Compressor [Member] \| Access Midstream Partners, L.P. [Member]
Property, Plant and Equipment [Line Items]
Proceeds from Sale of Property, Plant, and Equipment			159
Net gains (losses) on sales of fixed assets			(24)
Gathering and Processing Equipment [Member]
Property, Plant and Equipment [Line Items]
Net gains (losses) on sales of fixed assets	10	(109)	13	(179)
Gathering and Processing Equipment [Member] \| Granite Wash Midstream Gas Services, L.L.C. [Member]
Property, Plant and Equipment [Line Items]
Proceeds from Sale of Property, Plant, and Equipment		245
Net gains (losses) on sales of fixed assets	(106)
Gathering and Processing Equipment [Member] \| Sale to Western Gas Partners, LP [Member]
Property, Plant and Equipment [Line Items]
Proceeds from Sale of Property, Plant, and Equipment		134
Net gains (losses) on sales of fixed assets		(56)
Transportation Equipment [Member]
Property, Plant and Equipment [Line Items]
Proceeds from Sale of Property, Plant, and Equipment	44
Net gains (losses) on sales of fixed assets	23
Drilling Rigs [Member]
Property, Plant and Equipment [Line Items]
Equipment, Number of Units	14
Proceeds from Sale of Property, Plant, and Equipment	14
Net gains (losses) on sales of fixed assets			(14)
Land and Building [Member]
Property, Plant and Equipment [Line Items]
Net gains (losses) on sales of fixed assets	$ 1	$ 1	$ 1	$ 23