Benefit Plans (Schedule Of Defined Benefit Plans Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Net Unfunded Status of Plans [Roll Forward]
Service cost	$ (2,335)	$ (2,068)	$ (4,669)	$ (4,136)
Interest cost	(3,915)	(5,538)	(7,830)	(11,076)
Expected return on assets	10,454	9,445	20,908	18,890
Regulatory Assets Related to Pensions [Roll Forward]
Amortization of prior service cost	(736)	(919)	(1,472)	(1,838)
Defined Benefit Plan, Amortization of Gain (Loss)	$ (1,382)	$ (2,028)	$ (2,764)	$ (4,057)