Retirement Plans and Other Postretirement Benefits - Changes Benefit Obligations and Funded Status (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 04, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Benefits
Change in Benefit Obligation
Benefit obligation at the beginning of the period		$ 3,716,824	$ 3,902,867
Service cost		55,473	61,236	$ 56,233
Interest cost		107,492	98,566	118,567
Benefit payments		(212,565)	(207,928)
Actuarial (gain) loss		(857,695)	(137,917)
Benefit obligation at the end of the period		2,809,529	3,716,824	3,902,867
Change in Plan Assets
Balance at the beginning of the period		3,812,041	3,886,544
Actual return on plan assets		(787,874)	18,169
Employer contributions		0	100,000	100,000
Benefit payments		(194,682)	(192,672)
Transfer to active union medical account	$ 106,000	0	0
Balance at the end of the period		2,829,485	3,812,041	3,886,544
Funded Status at the end of the period		19,956	95,217
Other Benefits
Change in Benefit Obligation
Benefit obligation at the beginning of the period		591,841	624,034
Service cost		16,470	17,796	22,236
Interest cost		17,491	16,513	25,857
Benefit payments		(30,913)	(31,280)
Actuarial (gain) loss		(185,428)	(35,222)
Benefit obligation at the end of the period		409,461	591,841	624,034
Change in Plan Assets
Balance at the beginning of the period		872,435	961,165
Actual return on plan assets		(193,807)	41,432
Employer contributions		0	0
Benefit payments		(26,341)	(24,310)
Transfer to active union medical account	$ (106,000)	0	(105,852)
Balance at the end of the period		652,287	872,435	$ 961,165
Funded Status at the end of the period		$ 242,826	$ 280,594