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
Impairment of goodwill	$ (1,098)	(1,098)	$ 0	$ 0
Goodwill, end of period	47	47	1,120
Williams Partners [Member]
Goodwill [Line Items]
Goodwill, beginning of period		1,120
Goodwill, Purchase Accounting Adjustments		25
Impairment of goodwill		(1,098)
Goodwill, end of period	$ 47	$ 47	$ 1,120