Transactions with Affiliates (Details Textual) (USD $)	3 Months Ended			3 Months Ended				3 Months Ended		1 Months Ended	3 Months Ended
	Mar. 31, 2013 Employees	Mar. 31, 2012	Dec. 31, 2012	Mar. 31, 2013 Affiliated Entity [Member]	Mar. 31, 2012 Affiliated Entity [Member]	Mar. 31, 2013 Williams Partners L.P. [Member]	Dec. 31, 2012 Williams Partners L.P. [Member]	Mar. 31, 2013 Williams Field Services Company [Member]	Mar. 31, 2012 Williams Field Services Company [Member]	Apr. 30, 2013 Williams Partners Operating LLC [Member]	Mar. 31, 2013 Williams Partners Operating LLC [Member]	Mar. 31, 2012 Williams Partners Operating LLC [Member]	Mar. 31, 2013 The Williams Companies, Inc.[Member]	Mar. 31, 2012 The Williams Companies, Inc.[Member]
Related Party Transaction [Line Items]
Advances to affiliate	$ 385,343,000		$ 312,165,000			$ 385,300,000	$ 312,200,000
Related Party Transaction, Rate	0.01%
Total operating revenues	331,062,000	309,879,000		5,900,000	200,000
Cost of natural gas sales	24,571,000	10,146,000		2,400,000	1,300,000
Entity Number of Employees	0
Labor And Related Expense													45,900,000	51,000,000
Administrative and general	47,023,000	46,070,000		16,800,000	15,800,000
Total operating costs and expenses	229,301,000	216,421,000						(500,000)	(700,000)
Cash distributions to parent	65,000,000	54,259,000								58,000,000	65,000,000	54,300,000
Cash contributions from parent	$ 55,000,000	$ 34,000,000								$ 52,000,000	$ 55,000,000	$ 34,000,000