Accumulated Other Comprehensive Income (Loss) (AOCI balances) (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	$ 3,752,661	$ 4,411,669	$ 3,766,393
Other Comprehensive Income (Loss), Net of Tax	278,186	(635,237)	368,074
As of	4,001,868	3,752,661	4,411,669
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	336,151	971,388
Other comprehensive (loss) income before reclassifications	314,492	(585,143)
Net amount reclassified from accumulated other comprehensive income	(36,306)	(50,094)
Other Comprehensive Income (Loss), Net of Tax	278,186	(635,237)
As of	614,337	336,151	971,388
Foreign Currency Translation Adjustments [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	(54,638)	(6,298)
Other comprehensive (loss) income before reclassifications	21,927	(48,340)
Net amount reclassified from accumulated other comprehensive income	0	0
Other Comprehensive Income (Loss), Net of Tax	21,927	(48,340)	(16,052)
As of	(32,711)	(54,638)	(6,298)
Unrealized Gain (Loss) on Pensions and Other Postretirement Plans [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	388,591	979,157
Other comprehensive (loss) income before reclassifications	291,537	(540,079)
Net amount reclassified from accumulated other comprehensive income	(30,943)	(50,487)	(1,809)
Other Comprehensive Income (Loss), Net of Tax	260,594	(590,566)	383,870
As of	649,185	388,591	979,157
Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	2,198	(1,471)
Other comprehensive (loss) income before reclassifications	1,028	3,276
Net amount reclassified from accumulated other comprehensive income	(5,363)	393
Other Comprehensive Income (Loss), Net of Tax	(4,335)	3,669	256
As of	$ (2,137)	$ 2,198	$ (1,471)