Loans, Leases and Allowance for Credit Losses - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, unamortized loan fees	$ (106.0)	$ (108.0)
Financing receivable, unamortized premium	175.0	177.0
Loans Past Due 90 Days or More and Still Accruing	326.0	441.0
Interest income associated with loans on nonaccrual status	24.5	12.3	$ 4.7
Modified loans current with contractual payments	128.0	95.0
Modified loans on nonaccrual status	169.0	111.0
Amortized cost basis	297.0	206.0
Interest receivable	272.0	281.0
Loan sales	729.0
Carrying value of loans sold		(7,900.0)
Net gain (loss) on loan sales	(6.6)	(123.4)
Charge-offs	3.4
Sale of loans	4,900.0
Reclassification to HFI	2,400.0
Financing Receivable, Purchase
Financing Receivable, Allowance for Credit Loss [Line Items]
Loan purchases	1,700.0	1,600.0
Residential - EBO
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans Past Due 90 Days or More and Still Accruing	326.0	399.0
Amortized cost basis	366.0	225.0
Interest receivable	1.0	4.0
Loan purchases	385.0
Residential - EBO | Financial Asset, Current to 89 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Modified amount	29.0	26.0
Residential - EBO | Over 90 days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Modified amount	$ 11.0	$ 12.0