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, 2024	Dec. 31, 2023	Dec. 31, 2022
Net periodic benefit costs and the portion of these costs charged to expense
Portion of costs (credits) charged to expense	$ (48,870)	$ (40,648)	$ (98,487)
Pension Plans
Net periodic benefit costs and the portion of these costs charged to expense
Service cost-benefits earned during the period	43,641	39,461	55,473
Interest cost on benefit obligation	148,643	153,561	107,492
Expected return on plan assets	(188,651)	(182,938)	(185,775)
Prior service credit (a)	0	0	0
Net actuarial loss (gain)	41,915	38,420	17,515
Net periodic benefit costs (credits)	45,548	48,504	(5,295)
Portion of costs (credits) charged to expense	23,652	27,029	(16,431)
Other Benefits Plans
Net periodic benefit costs and the portion of these costs charged to expense
Service cost-benefits earned during the period	9,955	8,567	16,470
Interest cost on benefit obligation	22,169	22,509	17,491
Expected return on plan assets	(46,834)	(43,486)	(46,042)
Prior service credit (a)	(37,789)	(37,789)	(37,789)
Net actuarial loss (gain)	(8,676)	(9,614)	(12,835)
Net periodic benefit costs (credits)	(61,175)	(59,813)	(62,705)
Portion of costs (credits) charged to expense	$ (45,557)	$ (43,408)	$ (45,042)