Benefit Plans (Schedule Of Defined Benefit Plans Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net Unfunded Status of Plans [Roll Forward]
Service cost	$ (2,335)	$ (2,068)	$ (7,004)	$ (6,204)
Interest cost	(3,915)	(5,538)	(11,745)	(16,614)
Expected return on assets	10,454	9,445	31,362	28,335
Regulatory Assets Related to Pensions [Roll Forward]
Amortization of prior service cost	(736)	(920)	(2,208)	(2,758)
Defined Benefit Plan, Amortization of Gain (Loss)	$ (1,383)	$ (2,029)	$ (4,147)	$ (6,086)