Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Net income	$ 146,501	$ 155,651	$ 427,690	$ 495,422
Other comprehensive income (loss), before tax:
Change in net unrealized gain/loss on securities available for sale during the period	498,371	(600,441)	257,185	(547,035)
Change in net unrealized gain on securities transferred to held to maturity	(150)	(164)	(466)	(486)
Reclassification adjustment for net (gains) losses included in net income	(16)	(12)	(16)	(66)
Total securities available for sale and transferred securities, before tax amount	498,205	(600,617)	256,703	(547,587)
Defined-benefit post-retirement benefit plans:
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit)	418	869	1,255	2,609
Total defined-benefit post-retirement benefit plans	418	869	1,255	2,609
Other comprehensive income (loss), before tax	498,623	(599,748)	257,958	(544,978)
Deferred tax expense (benefit)	104,712	(125,948)	54,172	(114,445)
Other comprehensive income (loss), net of tax	393,911	(473,800)	203,786	(430,533)
Comprehensive income (loss)	$ 540,412	$ (318,149)	$ 631,476	$ 64,889