Investments (Schedule Of Investments) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Schedule of Invested Securities [Line Items]
Equity, Cost	$ 2,149	$ 2,149
Equity Method Investment Gross Unrealized Gains	2,203	2,370
Equity, Fair Value	4,352	4,519
Other, Cost	2,333	2,306
Other Gross Unrealized Gains	2,251	2,425
Other, Fair Value	4,584	4,731
Total Other	2,381	2,361
Total Investments	264,809	279,019
Total Nuclear Decommissioning Trust	256,860	276,658
Nuclear Decommissioning Trust [Member]
Schedule of Invested Securities [Line Items]
Investments, Debt securities, Cost	85,137	84,701
Investments, Debt securities, Gross Unrealized Gains		4,052
Investments, Debt securities, Gross Unrealized Losses	(3,285)
Investments, Debt securities	81,852	88,753
Investments, Equity securities, Cost	93,280	92,916
Investments, Equity securities, Gross Unrealized Gains	84,236	94,923
Investments, Equity securities, Gross Unrealized Losses	(2,926)	(408)
Investments, Equity securities	174,590	187,431
Investments, Cash and other	418	474
Investments, Cost	178,835	178,091
Investments, Gross Unrealized Gains	84,236	98,975
Investments, Gross Unrealized Loss	(6,211)	(408)
Total Nuclear Decommissioning Trust	256,860	276,658
Other [Member]
Schedule of Invested Securities [Line Items]
Investments, Equity securities, Cost	184	157
Investments, Equity securities, Gross Unrealized Gains	48	55
Total Investments	232	$ 212
Unrestricted Investments [Member]
Schedule of Invested Securities [Line Items]
Government obligations, Cost	5,568
Government obligations, Gross Unrealized Losses	(20)
Government obligations, Fair Value	5,548
Government obligations, Carrying Value	5,568
Unrestricted investments, Cost	5,568
Unrestricted investments, Gross Unrealized Losses	(20)
Unrestricted investments, Fair Value	5,548
Unrestricted investments, Carrying Value	$ 5,568