Other Borrowings - FHLB and FRB Borrowings (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
FHLB Advances
Outstanding advances	$ 0.0	$ 100.0
Asset Pledged as Collateral
FHLB Advances
Financing Receivable, Pledging Purpose [Extensible Enumeration]	Federal Funds Purchased	Federal Funds Purchased
Short term borrowings
FHLB Advances
Long-term Debt, Weighted Average Interest Rate, over Time	5.55%	5.08%
FRB Borrowings
FHLB Advances
Maximum borrowing capacity	$ 1,800.0
FRB Borrowings \| Asset Not Pledged as Collateral and Asset Pledged as Collateral without Right
FHLB Advances
Outstanding advances	1,800.0
Financing Receivable, after Allowance for Credit Loss	2,700.0
FHLB Advances
FHLB Advances
Average amount of FHLB advances outstanding	179.2	$ 243.0
Total borrowing capacity at FHLB	6,800.0
Letter of credit borrowed	3.3
Unused net credit available with the FHLB	6,800.0
FHLB Advances \| Industrial
FHLB Advances
Loans pledged via a blanket lien to the FHLB for advances and letters of credit	12,100.0
Debt Instrument Collateral Amount	6,700.0
FHLB Advances \| Investments Securities and Cash
FHLB Advances
Debt Instrument Collateral Amount	164.7
Investment securities pledged	193.7
FRB Borrowings
FHLB Advances
Letter of credit borrowed	$ 0.0	$ 0.0
FRB Borrowings \| Asset Not Pledged as Collateral and Asset Pledged as Collateral without Right
FHLB Advances
Financing Receivable, Pledging Purpose [Extensible Enumeration]	Federal Funds Purchased

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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Amount of assets pledged to secure a debt instrument.

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The calculated average balance outstanding for the year for all Federal Home Loan Bank advances as of the Balance Sheet date.

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Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

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Amount of maximum advances or credit lines available from the Federal Home Loan Bank (FHLB).

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Indicates pledging purpose of financing receivable.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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No definition available.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Weighted average interest rate of long-term debt outstanding calculated over time.

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Amortized cost, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

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The carrying amount (fair value) as of the balance sheet date of securities held that had been pledged by counterparties under financing and lending arrangements, pursuant to which the entity has the right by agreement or custom to sell or re-pledge such securities.

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