Retirement Plans and Other Postretirement Benefits - Net Periodic Benefit Costs and Portion including Portion Charged to Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net periodic benefit costs and the portion of these costs charged to expense
Portion of cost/(benefit) charged to expense	$ (98,487)	$ (112,541)	$ (56,341)
Pension Benefits
Net periodic benefit costs and the portion of these costs charged to expense
Service cost-benefits earned during the period	55,473	61,236	56,233
Interest cost on benefit obligation	107,492	98,566	118,567
Expected return on plan assets	(185,775)	(202,628)	(187,443)
Prior service credit	0	0	0
Net actuarial (gain)/loss	17,515	15,948	34,612
Net periodic benefit cost/(benefit)	(5,295)	(26,878)	21,969
Portion of cost/(benefit) charged to expense	(16,431)	(32,743)	3,386
Other Benefits
Net periodic benefit costs and the portion of these costs charged to expense
Service cost-benefits earned during the period	16,470	17,796	22,236
Interest cost on benefit obligation	17,491	16,513	25,857
Expected return on plan assets	(46,042)	(41,444)	(40,077)
Prior service credit	(37,789)	(37,705)	(37,575)
Net actuarial (gain)/loss	(12,835)	(10,093)	0
Net periodic benefit cost/(benefit)	(62,705)	(54,933)	(29,559)
Portion of cost/(benefit) charged to expense	$ (45,042)	$ (38,657)	$ (20,966)