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, 2021	Dec. 31, 2020	Dec. 31, 2019
Net periodic benefit costs and the portion of these costs charged to expense
Portion of cost/(benefit) charged to expense	$ (112,541)	$ (56,341)	$ (22,989)
Pension Benefits
Net periodic benefit costs and the portion of these costs charged to expense
Service cost-benefits earned during the period	61,236	56,233	49,902
Interest cost on benefit obligation	98,566	118,567	136,843
Expected return on plan assets	(202,628)	(187,443)	(171,884)
Prior service credit	0	0	0
Net actuarial (gain)/loss	15,948	34,612	42,584
Net periodic benefit cost/(benefit)	(26,878)	21,969	57,445
Portion of cost/(benefit) charged to expense	(32,743)	3,386	30,312
Other Benefits
Net periodic benefit costs and the portion of these costs charged to expense
Service cost-benefits earned during the period	17,796	22,236	18,369
Interest cost on benefit obligation	16,513	25,857	29,894
Expected return on plan assets	(41,444)	(40,077)	(38,412)
Prior service credit	(37,705)	(37,575)	(37,821)
Net actuarial (gain)/loss	(10,093)	0	0
Net periodic benefit cost/(benefit)	(54,933)	(29,559)	(27,970)
Portion of cost/(benefit) charged to expense	$ (38,657)	$ (20,966)	$ (19,859)