Benefit Plans (Schedule Of Defined Benefit Plans Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net Unfunded Status of Plans [Roll Forward]
Service cost	$ (2,334)	$ (2,068)
Interest cost	(3,915)	(5,538)
Expected return on assets	10,454	9,445
Regulatory Assets Related to Pensions [Roll Forward]
Amortization of prior service cost	(736)	(919)
Defined Benefit Plan, Amortization of Gain (Loss)	$ (1,382)	$ (2,029)