Pension and Postretirement Plans (Total Benefit/Cost) (Details 5) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Early retirement programs and special separation benefit expense	$ 4,606	$ 8,374	$ 22,700
Total Cost (Benefit) for the Year	(60,557)	(64,780)	(20,727)
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Current year actuarial gain (loss)	211,054	149,482	(762,806)
Current year prior service cost	0	1,600	0
Amortization of prior service credit (cost)	(275)	407	1,383
Recognized net actuarial gain (loss)	9,906	29,412	(3,096)
Curtailments and settlements	(51)	(8)	124,051
Total Recognized in Other Comprehensive Income (Before Tax Effects)	219,800	180,893	(640,468)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	26,294	27,792	46,115
Interest cost	52,613	51,825	55,821
Expected return on assets	(130,571)	(120,472)	(105,574)
Amortization of prior service cost (credit)	320	329	2,809
Recognized actuarial loss (gain)	(11,925)	(28,880)	2,756
Net Periodic Cost (Benefit) for the Year	(63,269)	(69,406)	1,927
Curtailment	(3,267)	0	(43,930)
Settlement	0	0	39,995
Early retirement programs and special separation benefit expense	4,606	8,374	22,700
Total Cost (Benefit) for the Year	(61,930)	(61,032)	20,692
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Current year actuarial gain (loss)	222,894	125,866	(750,328)
Amortization of prior service credit (cost)	(320)	(329)	(2,809)
Recognized net actuarial gain (loss)	11,925	28,880	(2,756)
Curtailments and settlements	(51)	(368)	94,520
Total Recognized in Other Comprehensive Income (Before Tax Effects)	234,448	154,049	(661,373)
Total Recognized in Total (Benefit) Cost and Other Comprehensive Income (Before Tax Effects)	172,518	93,017	(640,681)
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,946	1,493	1,612
Interest cost	4,550	4,397	4,148
Amortization of prior service cost (credit)	457	47	55
Recognized actuarial loss (gain)	3,015	1,544	2,481
Net Periodic Cost (Benefit) for the Year	9,968	7,481	8,296
Settlement	0	0	(2,575)
Early retirement programs and special separation benefit expense	0	2,422	0
Total Cost (Benefit) for the Year	9,968	9,903	5,721
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Current year actuarial gain (loss)	(6,544)	19,168	(9,180)
Current year prior service cost	0	1,600	0
Amortization of prior service credit (cost)	(457)	(47)	(55)
Recognized net actuarial gain (loss)	(3,015)	(1,544)	(2,481)
Curtailments and settlements	(834)	0	(2,798)
Total Recognized in Other Comprehensive Income (Before Tax Effects)	(10,850)	19,177	(14,514)
Total Recognized in Total (Benefit) Cost and Other Comprehensive Income (Before Tax Effects)	(882)	29,080	(8,793)
Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,331	1,500	2,488
Interest cost	1,299	1,448	1,848
Amortization of prior service cost (credit)	(502)	(783)	(4,247)
Recognized actuarial loss (gain)	(996)	(2,076)	(2,141)
Net Periodic Cost (Benefit) for the Year	1,132	89	(2,052)
Curtailment	0	(1,292)	(41,623)
Settlement	0	0	(11,927)
Total Cost (Benefit) for the Year	1,132	(1,203)	(55,602)
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Current year actuarial gain (loss)	(5,296)	4,448	(3,298)
Amortization of prior service credit (cost)	502	783	4,247
Recognized net actuarial gain (loss)	996	2,076	2,141
Curtailments and settlements	0	360	32,329
Total Recognized in Other Comprehensive Income (Before Tax Effects)	(3,798)	7,667	35,419
Total Recognized in Total (Benefit) Cost and Other Comprehensive Income (Before Tax Effects)	$ (2,666)	$ 6,464	$ (20,183)