Retirement Plans and Other Postretirement Benefits - Changes Benefit Obligations and Funded Status (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 04, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Change in Benefit Obligation
Benefit obligation at the beginning of the period		$ 3,902,867	$ 3,613,114
Service cost		61,236	56,233	$ 49,902
Interest cost		98,566	118,567	136,843
Benefit payments		(207,928)	(191,704)
Actuarial (gain) loss		(137,917)	306,657
Benefit obligation at the end of the period		3,716,824	3,902,867	3,613,114
Change in Plan Assets
Balance at the beginning of the period		3,886,544	3,318,351
Actual return on plan assets		18,169	642,373
Employer contributions		100,000	100,000	150,000
Benefit payments		(192,672)	(174,180)
Transfer to active union medical account	$ 106,000	0	0
Balance at the end of the period		3,812,041	3,886,544	3,318,351
Funded Status at the end of the period		95,217	(16,323)
Other Benefits
Change in Benefit Obligation
Benefit obligation at the beginning of the period		624,034	746,924
Service cost		17,796	22,236	18,369
Interest cost		16,513	25,857	29,894
Benefit payments		(31,280)	(31,511)
Actuarial (gain) loss		(35,222)	(139,472)
Benefit obligation at the end of the period		591,841	624,034	746,924
Change in Plan Assets
Balance at the beginning of the period		961,165	837,494
Actual return on plan assets		41,432	150,076
Employer contributions		0	0
Benefit payments		(24,310)	(26,405)
Transfer to active union medical account	$ (106,000)	(105,852)	0
Balance at the end of the period		872,435	961,165	$ 837,494
Funded Status at the end of the period		$ 280,594	$ 337,131