Transactions with Major Customers and Affiliates (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) employee	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Related Party Transaction [Line Items]
Advances to affiliate		$ 281,442	$ 247,869
Related party transaction, rate		0.01%
Interest Income, affiliate			600	$ 4,100
Entity number of employees | employee		0
Related party transaction, expenses from transactions with related party		$ 85,200	77,900	84,500
Cash distributions to parent		(166,500)	(164,000)	(110,000)
Williams Companies Inc [Member]
Related Party Transaction [Line Items]
Advances to affiliate		281,400	247,900
Cash distributions to parent		166,500	164,000	110,000
Subsequent Event [Member]
Related Party Transaction [Line Items]
Cash distributions to parent	$ 42,000
Puget Sound Energy, Inc.
Revenue, Major Customer [Line Items]
Operating revenues		131,462	132,747	121,792
Northwest Natural Gas Company
Revenue, Major Customer [Line Items]
Operating revenues		49,078	47,493	46,969
Cascade Natural Gas Corporation
Revenue, Major Customer [Line Items]
Operating revenues		$ 48,901	$ 48,893	$ 48,891