Transactions with Major Customers and Affiliates (Details) (USD $)	1 Months Ended	12 Months Ended
	Jan. 31, 2014	Dec. 31, 2013 employee	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]
Advances to affiliate		$ 526,380,000	$ 312,165,000
Related party transaction, rate		0.01%
Operating revenues, related party		16,300,000	17,000,000	18,500,000
Purchases, related party		6,900,000	3,900,000	8,800,000
Entity number of employees		0
Expenses, related party		310,300,000	320,100,000	278,600,000
Equity distributions	112,000,000	250,000,000	246,259,000	219,000,000
Cash contributions from parent		264,000,000	150,000,000	115,000,000
Public Service Enterprise Group [Member]
Revenue, Major Customer [Line Items]
Operating revenues		130,700,000	127,400,000	136,700,000
National Grid [Member]
Revenue, Major Customer [Line Items]
Operating revenues		88,500,000	93,500,000	98,200,000
Williams Partners L.P. [Member]
Related Party Transaction [Line Items]
Advances to affiliate		526,400,000	312,200,000
Williams Field Services [Member]
Related Party Transaction [Line Items]
Expenses, related party		(2,300,000)	(4,500,000)	(6,400,000)
Reimbursements and pre-payments for capital projects		3,600,000	2,300,000	4,500,000
Williams Gas Processing - Gulf Coast Company, L.P. [Member]
Related Party Transaction [Line Items]
Reimbursement			3,100,000
Williams Partners Operating LLC [Member]
Related Party Transaction [Line Items]
Cash contributions from parent	54,000,000	264,000,000	150,000,000	115,000,000
Non-cash contributions from parent			1,500,000
Non-cash return of capital to parent				$ 500,000