Transactions with Major Customers and Affiliates (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) employee	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Revenue, Major Customer [Line Items]
Operating revenues		$ 447,335	$ 443,558	$ 449,482
Related Party Transaction [Line Items]
Advances to affiliate		$ 310,641	281,442
Related party transaction, rate		4.00%
Interest Income, affiliate		$ 4,900		600
Entity number of employees | employee		0
Related party transaction, expenses from transactions with related party		$ 87,700	85,200	77,900
Cash distributions to parent		137,900	166,500	164,000
Williams Companies Inc [Member]
Related Party Transaction [Line Items]
Advances to affiliate		310,600	281,400
Subsequent Event [Member]
Related Party Transaction [Line Items]
Cash distributions to parent	$ 35,800
Puget Sound Energy, Inc.
Revenue, Major Customer [Line Items]
Operating revenues		130,705	131,462	132,747
Northwest Natural Gas Company
Revenue, Major Customer [Line Items]
Operating revenues		48,921	48,901	48,893
Cascade Natural Gas Corporation
Revenue, Major Customer [Line Items]
Operating revenues		$ 48,664	$ 49,078	$ 47,493