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, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6,508	$ 6,159	$ 5,081
Interest cost	17,020	17,012	19,184
Expected return on plan assets	(18,999)	(20,804)	(24,512)
Amortization of prior service cost (credit)	518	605	748
Amortization of actuarial loss	16,339	17,937	14,451
Net periodic cost (benefit)	21,386	20,909	14,952
Other Postretirement Employee Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	14	22	25
Interest cost	1,421	1,456	1,741
Amortization of prior service cost (credit)	(8,877)	(9,312)	(9,641)
Amortization of actuarial loss	1,717	2,047	2,186
Net periodic cost (benefit)	$ (5,725)	$ (5,787)	$ (5,689)