Transactions with Affiliates (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended					9 Months Ended		1 Months Ended
	Sep. 30, 2014 employee	Sep. 30, 2013	Sep. 30, 2014 employee	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 Affiliated Entity [Member]	Sep. 30, 2013 Affiliated Entity [Member]	Sep. 30, 2014 Affiliated Entity [Member]	Sep. 30, 2013 Affiliated Entity [Member]	Sep. 30, 2014 Williams Partners L.P. [Member]	Dec. 31, 2013 Williams Partners L.P. [Member]	Mar. 31, 2014 Williams Field Services Group, LLC [Member]	Sep. 30, 2014 Williams Partners Operating LLC [Member]	Sep. 30, 2013 Williams Partners Operating LLC [Member]	Oct. 31, 2014 Subsequent Event [Member] Williams Partners Operating LLC [Member]
Related Party Transaction [Line Items]
Advances to affiliate	$ 412,225,000		$ 412,225,000		$ 526,380,000					$ 412,200,000	$ 526,400,000
Related party transaction, rate			0.01%
Operating revenues, related party	3,500,000	1,600,000	6,300,000	14,100,000
Cost of natural gas sales, related party	1,300,000	1,700,000	8,100,000	5,700,000
Entity number of employees	0		0
Expenses, related party	73,900,000	79,500,000	223,600,000	233,000,000		(1,600,000)	(1,600,000)	(4,800,000)	(5,000,000)
Pre-payments for capital projects												4,200,000
Equity distributions			318,000,000	186,000,000									318,000,000	186,000,000	93,000,000
Contributions			$ 164,000,000	$ 203,000,000									$ 164,000,000	$ 203,000,000	$ 103,000,000