Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Pre-Tax Components Of Net Periodic Cost (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8,454	$ 6,753	$ 6,508
Interest cost	16,992	16,096	17,020
Expected return on plan assets	(20,035)	(18,406)	(18,999)
Amortization of prior service cost (credit)	186	288	518
Amortization of actuarial loss	16,589	14,484	16,339
Net periodic cost (benefit)	22,186	19,215	21,386
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	341	14	14
Interest cost	1,482	1,262	1,421
Amortization of prior service cost (credit)	(8,877)	(8,877)	(8,877)
Amortization of actuarial loss	1,311	1,537	1,717
Net periodic cost (benefit)	$ (5,743)	$ (6,064)	$ (5,725)