Goodwill (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Goodwill, beginning of period		$ 1,120
Goodwill, Purchase Accounting Adjustments		25
Impairment of goodwill	$ (1,098)	(1,098)	$ 0	$ 0
Goodwill, end of period	47	47	1,120
West [Member]
Goodwill [Line Items]
Goodwill, beginning of period		45
Goodwill, Purchase Accounting Adjustments		2
Impairment of goodwill		0
Goodwill, end of period	47	47	45
Access Midstream [Member]
Goodwill [Line Items]
Goodwill, beginning of period		429
Goodwill, Purchase Accounting Adjustments		23
Impairment of goodwill		(452)
Goodwill, end of period	0	0	429
Northeast G&P [Member]
Goodwill [Line Items]
Goodwill, beginning of period		646
Goodwill, Purchase Accounting Adjustments		0
Impairment of goodwill		(646)
Goodwill, end of period	$ 0	$ 0	$ 646