Transactions with Major Customers and Affiliates (Details) (USD $)	1 Months Ended	12 Months Ended
	Jan. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]
Advances to affiliate		$ 119,168,000	$ 29,322,000
Related party transaction, rate		0.01%
Entity number of employees		0
Related party transaction, expenses from transactions with related party		112,100,000	113,000,000	98,000,000
Related party transaction, other revenues from transactions with related party				24,700,000
Equity distributions to parent		91,000,000	137,500,000	127,000,000
Contributions from parent		13,300,000	8,630,000	5,100,000
Puget Sound Energy, Inc. [Member]
Revenue, Major Customer [Line Items]
Operating revenues		110,111,000	100,799,000	99,116,000
Northwest Natural Gas Company [Member]
Revenue, Major Customer [Line Items]
Operating revenues		51,085,000	47,297,000	47,322,000
Williams Field Services [Member]
Related Party Transaction [Line Items]
Reimbursable costs		89,800,000
Related party transaction, due from (to) related party		38,600,000
Williams Partners L.P. [Member]
Related Party Transaction [Line Items]
Advances to affiliate		119,200,000	29,300,000
Williams Partners Operating LLC [Member]
Related Party Transaction [Line Items]
Equity distributions to parent	52,000,000	91,000,000	137,500,000	127,000,000
Contributions from parent		$ 13,300,000	$ 8,600,000	$ 5,100,000