Liquidity Facilities and Other Financing Arrangements (Details) - USD ($) $ in Thousands			12 Months Ended
	Sep. 26, 2022	Feb. 10, 2012	Dec. 31, 2022	May 16, 2022	Dec. 31, 2021
Short-term Debt [Line Items]
Short-term debt			$ 441,300		$ 140,000
Line of Credit Facility, Maximum Borrowing Capacity			1,300,000
Proceeds from Lines of Credit	$ 50,000
Line of Credit, Current			84,300
Working Capital Needs
Short-term Debt [Line Items]
Current borrowing capacity of line of credit				$ 800,000
Subsidiaries [Member]
Short-term Debt [Line Items]
Short-term debt			$ 357,000		$ 140,000
Weighted-average interest rate on short-term debt (percent)			6.10%		1.60%
Line of Credit Facility, Current Same-Day Borrowing Capacity			$ 75,000
Line of Credit Facility, Maximum Borrowing Capacity			$ 1,400,000
Maximum capitalization percentage			65.00%
Derivative, Basis Spread on Variable Rate			1.25%
Line of Credit, Unused Capacity, Commitment Fee Percentage			0.175%
Promissory Note Outstanding, Amount			$ 0
Subsidiaries [Member] | Working Capital Needs
Short-term Debt [Line Items]
Current borrowing capacity of line of credit				$ 800,000
Subsidiaries [Member] | Letter of Credit | Working Capital Needs
Short-term Debt [Line Items]
Current borrowing capacity of line of credit			2,300
Subsidiaries [Member] | Letter of Credit | Energy Dedging Activities
Short-term Debt [Line Items]
Current borrowing capacity of line of credit			28,000
Subsidiaries [Member] | Line of Credit [Member] | Promissory Note with Puget Energy
Short-term Debt [Line Items]
Current borrowing capacity of line of credit			$ 30,000
Basis spread on variable rate (percent)			0.25%
Debt instrument variable rate basis			one-month LIBOR
Parent
Short-term Debt [Line Items]
Short-term debt			$ 84,300		$ 0
Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Basis spread on variable rate (percent)			1.75%
Line of Credit Facility, Commitment Fee Percentage		0.275%
Line of Credit Facility, Fair Value of Amount Outstanding			$ 118,600
Debt Instrument, Secured Overnight Financing Rate Adjustment			0.10%
Revolving Credit Facility [Member] | Subsidiaries [Member]
Short-term Debt [Line Items]
Line of Credit Facility, Fair Value of Amount Outstanding			$ 0
Debt Instrument, Secured Overnight Financing Rate Adjustment			0.10%