Transactions with Major Customers and Affiliates (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2024 USD ($)	Dec. 31, 2023 USD ($) employee	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Revenue, Major Customer [Line Items]
Operating revenues		$ 439,858	$ 447,335	$ 443,558
Related Party Transaction [Line Items]
Related party transaction, rate		5.20%
Entity number of employees | employee		0
Cash distributions to parent		$ 154,800	137,900	166,500
Related Party [Member]
Related Party Transaction [Line Items]
Advances to affiliate		157,776	310,641
Interest Income, affiliate		8,300		4,900
Related party transaction, expenses from transactions with related party		86,000	87,700	85,200
Williams Companies Inc [Member]
Related Party Transaction [Line Items]
Advances to affiliate		157,800	310,600
Subsequent Event [Member]
Related Party Transaction [Line Items]
Cash distributions to parent	$ 33,000
Puget Sound Energy, Inc.
Revenue, Major Customer [Line Items]
Operating revenues		126,206	130,705	131,462
Northwest Natural Gas Company
Revenue, Major Customer [Line Items]
Operating revenues		46,637	48,921	48,901
Cascade Natural Gas Corporation
Revenue, Major Customer [Line Items]
Operating revenues		$ 47,046	$ 48,664	$ 49,078