Retirement Plans and Other Postretirement Benefits - Changes Benefit Obligations and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Plans
Change in Benefit Obligation
Benefit obligation at the beginning of the period	$ 2,908,063	$ 2,809,529
Service cost	43,641	39,461	$ 55,473
Interest cost	148,643	153,561	107,492
Benefit payments	(216,238)	(210,737)
Actuarial (gain) loss	(91,800)	116,249
Benefit obligation at the end of the period	2,792,309	2,908,063	2,809,529
Change in Plan Assets
Balance at the beginning of the period	2,835,549	2,829,485
Actual return on plan assets	4,518	199,098
Benefit payments	(200,205)	(193,034)
Balance at the end of the period	2,639,862	2,835,549	2,829,485
Funded/(Underfunded) Status at the end of the period	(152,447)	(72,514)
Other Benefits Plans
Change in Benefit Obligation
Benefit obligation at the beginning of the period	430,434	409,461
Service cost	9,955	8,567	16,470
Interest cost	22,169	22,509	17,491
Benefit payments	(30,516)	(30,784)
Actuarial (gain) loss	(71,952)	20,681
Benefit obligation at the end of the period	360,090	430,434	409,461
Change in Plan Assets
Balance at the beginning of the period	696,494	652,287
Actual return on plan assets	32,816	67,317
Benefit payments	(27,118)	(23,110)
Balance at the end of the period	702,192	696,494	$ 652,287
Funded/(Underfunded) Status at the end of the period	$ 342,102	$ 266,060