Summary of Significant Accounting Policies (Details) $ in Thousands		12 Months Ended
	Dec. 19, 2017	Dec. 31, 2021 USD ($) mi²	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jan. 01, 2018 USD ($)
Accounting Policies
Excise taxes collected		$ 268,500	$ 240,800	$ 236,500
Allowance for doubtful accounts		34,958	20,080
Monetized production tax credits		$ 45,600	39,800
PTC, Operation Period		10 years
Bad Debt Deferral, COVID 19		$ 2,800	$ 0
Electric Transmission
Accounting Policies
Annual depreciation provision		3.40%	3.50%	3.40%
Gas Transmission Equipment
Accounting Policies
Annual depreciation provision		2.80%	2.90%	2.80%
Common Plant
Accounting Policies
Annual depreciation provision		6.80%	7.30%	7.30%
Subsidiaries [Member]
Accounting Policies
Area of service territory (sqmi) | mi²		6,000
Allowance for doubtful accounts		$ (34,958)	$ (20,080)
Public Utilities, Rate Case, Deferred Storm Costs Threshold					$ 10,000
Variable Interest Entity, Measure of Activity, Expense		$ 19,000	4,200
Contract Length, PPA		20 years
Variable Interest Entity, Payable		$ 2,700
Regulatory Asset, Amortization Period		1 year
Regulatory Liability, Amortization Period		1 year
Puget LNG [Member]
Accounting Policies
Jointly Owned Non-Utility Plant Share		57.00%
Construction in Progress, Gross		$ 244,700	231,600
Operating Costs and Expenses		$ 1,300	600	$ 1,200
Tacoma LNG [Member]
Accounting Policies
Jointly Owned Non-Utility Plant Share		43.00%
Construction in Progress, Gross		$ 239,600	$ 207,700
Decoupling Mechanism [Member] | Electricity, US Regulated [Member] | Subsidiaries [Member] | Maximum
Accounting Policies
Public Utilities, Approved Rate Increase (Decrease), Percentage	3.00%
Decoupling Mechanism [Member] | Natural Gas [Member] | Subsidiaries [Member] | Maximum
Accounting Policies
Public Utilities, Approved Rate Increase (Decrease), Percentage	5.00%