Accumulated Other Comprehensive Income (Loss) (AOCI balances) (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	$ 3,766,393	$ 3,326,796
Other Comprehensive Loss, Net of Tax	(1,203)	(37,943)
As of	3,864,839	3,212,840
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	603,314
Other comprehensive (loss) income before reclassifications	(163)
Net amount reclassified from accumulated other comprehensive income (loss)	(1,040)
Other Comprehensive Loss, Net of Tax	(1,203)
As of	602,111
Cumulative Foreign Currency Translation Adjustment [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	9,754
Other comprehensive (loss) income before reclassifications	(486)
Net amount reclassified from accumulated other comprehensive income (loss)	0
Other Comprehensive Loss, Net of Tax	(486)	(37,376)
As of	9,268
Unrealized Gain on Pensions and Other Postretirement Plans [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	595,287
Other comprehensive (loss) income before reclassifications	0
Net amount reclassified from accumulated other comprehensive income (loss)	(1,194)	650
Other Comprehensive Loss, Net of Tax	(1,194)	650
As of	594,093
Cash Flow Hedges [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	(1,727)
Other comprehensive (loss) income before reclassifications	323
Net amount reclassified from accumulated other comprehensive income (loss)	154
Other Comprehensive Loss, Net of Tax	477	$ (1,217)
As of	$ (1,250)