Regulatory Capital - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Jan. 01, 2020	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Allowance for credit losses on loans and leases			$ 1,339,772	$ 1,357,075	$ 1,165,335	$ 1,361,723
Liability for unfunded commitments			112,962	124,924	72,713	$ 110,044
Unrealized gain (loss)		$ (160,000)	(115,000)
Gain (loss) OCI after adjustment tax		$ (52,000)	(37,000)
Dividends			$ 550,000	$ 700,000	$ 1,400,000
Accounting Standards Update 2016-13
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Period of deferment	2 years
Amount deferred	25.00%
Allowance for credit losses on loans and leases	$ 1,100,000
Liability for unfunded commitments	116,000
Deferred tax asset	306,000
Reduction to retained earnings	$ 953,000