Accumulated Other Comprehensive (Loss), Net of Tax - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Tax benefit	$ (56,737)	$ (69,346)
Interest payments	755,117	792,045
Premium amortization	973,487	951,850
Actuarial net loss amortization	(30,728)	(31,429)
Net income	226,917	216,323
Cash Flow Hedging
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Estimate of amount to be reclassified from AOCL	1,300
Investment Securities Available- for-Sale | Reclassification out of accumulated comprehensive income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net unrealized gains (losses)	528	(8,688)
Tax benefit	(143)	2,368
Net income	385	(6,320)
Derivative Financial Instruments | Reclassification out of accumulated comprehensive income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Tax benefit	883	2,850
Interest payments	(3,255)	(10,492)
Hedge terminations	0	(34)
Premium amortization	0	(272)
Net income	(2,372)	(7,948)
Defined benefit pension and other postretirement benefit plans: | Reclassification out of accumulated comprehensive income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Tax benefit	103	178
Net income	(277)	(479)
Actuarial net loss amortization | Reclassification out of accumulated comprehensive income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Actuarial net loss amortization	$ (380)	$ (657)