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Securities - Narrative (Details)	12 Months Ended
Securities - Narrative (Details)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022	Dec. 31, 2022 holding	Jan. 01, 2022 USD ($)
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, allowance for credit loss, excluding accrued interest	$ 0		$ 0			$ 0
Debt securities, available-for-sale, accrued interest, after allowance for credit loss	$ 9,200,000		12,900,000
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Debt securities, available-for-sale, accrued interest writeoff	$ 0	$ 0
Number of holdings	736			802
Debt securities, held-to-maturity, allowance for credit loss, excluding accrued interest	$ 0		0
Debt securities, held-to-maturity, accrued interest, after allowance for credit loss	$ 900,000		1,000,000
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Debt securities, held-to-maturity, accrued interest, writeoff	$ 0	$ 0
Debt securities, available-for-sale and held-to-maturity, fair value	4,812,343,000		7,114,004,000
Carrying value of securities pledged as collateral	615,700,000		437,900,000
Bank Term Funding Program
Debt Securities, Available-for-sale [Line Items]
Carrying value of securities pledged as collateral	2,400,000,000		0
Federal Reserve Discount Window
Debt Securities, Available-for-sale [Line Items]
Carrying value of securities pledged as collateral	168,800,000		0
Callable Securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale and held-to-maturity, fair value	$ 394,400,000		852,900,000
Other debt securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, allowance for credit loss, excluding accrued interest			$ 0
Number of holdings				2	2
Foreign Debt Securities
Debt Securities, Available-for-sale [Line Items]
Number of holdings \| holding					2