CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 182,844	$ 249,625	$ 528,445	$ 673,906
Other comprehensive income (loss), net of tax:
Change in unrealized investment gains and losses	(75,221)	(153,615)	(24,796)	(599,933)
Benefit plan adjustments	3,213	(16,172)	9,412	(15,289)
Other comprehensive income (loss), net of tax	(72,008)	(169,787)	(15,384)	(615,222)
Comprehensive income (loss)	$ 110,836	$ 79,838	$ 513,061	$ 58,684