Regulatory and Rate Matters - Schedule of Change in Balance Sheet Related to Discontinued Services (Details) - USD ($) $ in Thousands		9 Months Ended
	Sep. 29, 2022	Sep. 30, 2022	Sep. 30, 2021
Current Assets:
Inventory	$ (6,430)	$ 6,630	$ 333
Utility Plant:
Net utility plant	(382,798)
Deferred Charges and Other Assets:
Regulatory assets - ETA	289,381
Regulatory Assets - Non-ETA	22,593
Deferred Credits and Other Liabilities:
Regulatory liabilities (3)	(77,254)
Net increase (decrease)	$ 0
Undepreciated investments		274,900
Investments, plant decommissioning		14,500
Obsolete inventory		6,400
Inventory, plant decommissioning		$ 16,200