Accumulated Other Comprehensive Loss (Components of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	$ 5,804,611
Components of other comprehensive income (loss):
Other comprehensive (loss) income	(127,823)	$ 28,788
Balance at end of period	5,098,303	$ 5,326,677
Reclassifications before taxes, included in net periodic benefit expense	379
Reclassifications, income tax expense	80
Foreign Currency Translation Gains (Losses)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(353,252)
Components of other comprehensive income (loss):
Before reclassifications to income and retained earnings	(118,411)
Reclassifications to income	0
Other comprehensive (loss) income	(118,411)
Balance at end of period	(471,663)
Retirement and Postretirement Benefit Plan Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(218,015)
Components of other comprehensive income (loss):
Before reclassifications to income and retained earnings	(13,054)
Reclassifications to income	3,343
Other comprehensive (loss) income	(9,711)
Balance at end of period	(227,726)
Reclassifications before taxes, included in net periodic benefit expense	4,250
Deferred Loss on Interest Rate Derivative Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(2,894)
Components of other comprehensive income (loss):
Before reclassifications to income and retained earnings	0
Reclassifications to income	299
Other comprehensive (loss) income	299
Balance at end of period	(2,595)
Reclassifications, income tax expense	907
AOCI Including Portion Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(574,161)
Components of other comprehensive income (loss):
Before reclassifications to income and retained earnings	(131,465)
Reclassifications to income	3,642
Other comprehensive (loss) income	(127,823)
Balance at end of period	$ (701,984)