Pension and Postretirement Plans (Total Benefit/Cost) (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5,775	$ 5,457	$ 17,254	$ 17,044
Special separation benefit expense		7,783		13,797
Net Periodic Cost (Benefit)			(68,644)	(27,669)
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5,775	5,457	17,254	17,044
Interest cost	6,754	8,139	20,162	24,448
Expected return on assets	(34,800)	(28,347)	(103,078)	(85,081)
Amortization of prior service cost (credit)	711	708	2,134	2,123
Recognized actuarial loss (gain)	(1,671)	0	(6,234)	0
Net Periodic Cost (Benefit)	(23,231)	(14,043)	(69,762)	(41,466)
Special separation benefit expense	0	7,783	1,118	13,797
Net Periodic Cost (Benefit)	(23,231)	(6,260)	(68,644)	(27,669)
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	256	238	767	715
Interest cost	736	920	2,207	2,759
Amortization of prior service cost (credit)	83	83	248	248
Recognized actuarial loss (gain)	1,482	1,316	4,447	3,950
Net Periodic Cost (Benefit)	2,557	2,557	7,669	7,672
Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	23	41	69	125
Amortization of prior service cost (credit)	(1)	(120)	(5)	(361)
Recognized actuarial loss (gain)	(877)	(1,012)	(2,632)	(3,036)
Net Periodic Cost (Benefit)	$ (855)	$ (1,091)	$ (2,568)	$ (3,272)