SCHEDULE I CONDENSED FINANCIAL INFORMATION OF PUGET ENERGY - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Property And Investments [Abstract]
Goodwill	$ 1,656,513	$ 1,656,513
Current assets:
Cash and Cash Equivalents, at Carrying Value	56,946	52,307
Total current assets	1,138,108	916,617
Assets, Noncurrent [Abstract]
Other	163,374	80,751
Total assets	15,871,884	15,042,965
Capitalization, Long-term Debt and Equity [Abstract]
Stockholders' Equity Attributable to Parent	4,563,316	4,139,882	$ 4,000,299	$ 3,860,758
Long-term debt	1,583,300	1,724,700
Total capitalization	10,767,082	10,032,322
Current liabilities:
Accounts payable	444,384	342,404
Current maturities of long-term debt	450,000	526,412
Interest	67,807	73,647
Unrealized loss on derivative instruments	63,309	31,441
Total current liabilities	1,425,423	1,595,614
Liabilities, Noncurrent [Abstract]
Unrealized loss on derivative instruments	40,965	29,833
Total capitalization and liabilities	15,871,884	15,042,965
Parent
Assets
Investments in subsidiaries	4,446,758	4,279,501
Other Property And Investments [Abstract]
Goodwill	1,656,513	1,656,513
Current assets:
Cash and Cash Equivalents, at Carrying Value	6,386	790
Receivables from affiliates	233,258	211,411
Income Taxes Receivable, Current	6,006	0
Total current assets	245,650	212,201
Assets, Noncurrent [Abstract]
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	250,820	258,033
Other	984	1,520
Assets, Noncurrent, Total	251,804	259,553
Total assets	6,600,725	6,407,768
Capitalization, Long-term Debt and Equity [Abstract]
Stockholders' Equity Attributable to Parent	4,563,316	4,139,882
Long-term debt	1,571,287	1,714,744
Total capitalization	6,134,603	5,854,626
Current liabilities:
Accounts payable	147	349
Accrued Income Taxes, Current	0	3,334
Current maturities of long-term debt	450,000	524,000
Interest	15,975	25,459
Total current liabilities	466,122	553,142
Liabilities, Noncurrent [Abstract]
Total capitalization and liabilities	$ 6,600,725	$ 6,407,768