Loans and Leases - Modifications to Borrowers Experiencing Financial Difficulty (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 1.0
% of Total Class	0.00%	0.00%
Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 227.0	$ 125.0
% of Total Class	0.40%	0.20%
Principal Forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 1.0
% of Total Class	0.00%	0.00%
Payment Deferrals
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 3.0
% of Total Class	0.00%	0.00%
Combination - Term Extension and Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 3.0	$ 5.0
% of Total Class	0.00%	0.00%
Combination - Term Extension, Interest Rate Reduction, and Interest Forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 2.0
% of Total Class	0.00%	0.00%
Combination - Term Extension, Interest Rate Reduction, and Interest Deferrals
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 16.0
% of Total Class	0.00%	0.00%
Consumer: | Consumer Real Estate | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 1.0
% of Total Class	0.00%	0.00%
Consumer: | Consumer Real Estate | Interest Rate Reduction | Maximum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Weighted average interest rate of loans	9.93%	8.60%
Consumer: | Consumer Real Estate | Interest Rate Reduction | Minimum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Weighted average interest rate of loans	6.56%	5.00%
Consumer: | Consumer Real Estate | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 2.0
% of Total Class	0.00%	0.00%
Weighted average life of loans	22 years	10 years
Consumer: | Consumer Real Estate | Principal Forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 1.0
% of Total Class	0.00%	0.00%
Decrease from loan modification	$ 1.0	$ 1.3
Consumer: | Consumer Real Estate | Payment Deferrals
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 3.0
% of Total Class	0.00%	0.00%
Weighted average life of loans		11 months
Consumer: | Consumer Real Estate | Combination - Term Extension and Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 3.0	$ 5.0
% of Total Class	0.00%	0.00%
Weighted average life of loans	10 years 10 months 24 days	13 years 6 months
Consumer: | Consumer Real Estate | Combination - Term Extension and Interest Rate Reduction | Maximum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Weighted average interest rate of loans	8.66%	5.60%
Consumer: | Consumer Real Estate | Combination - Term Extension and Interest Rate Reduction | Minimum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Weighted average interest rate of loans	4.06%	4.80%
Consumer: | Credit Card and Other | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 0.0
% of Total Class	0.00%	0.00%
Consumer: | Credit Card and Other | Interest Rate Reduction | Maximum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Weighted average interest rate of loans	4.78%	13.30%
Consumer: | Credit Card and Other | Interest Rate Reduction | Minimum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Weighted average interest rate of loans	3.65%	0.00%
Commercial: | Commercial and industrial | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 111.0	$ 81.0
% of Total Class	0.30%	0.20%
Weighted average life of loans	1 year 4 months 24 days	1 year
Commercial: | Commercial and industrial | Combination - Term Extension, Interest Rate Reduction, and Interest Forgiveness
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 2.0
% of Total Class	0.00%	0.00%
Weighted average life of loans		3 years 8 months 12 days
Decrease from loan modification		$ 1.0
Commercial: | Commercial and industrial | Combination - Term Extension, Interest Rate Reduction, and Interest Forgiveness | Maximum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Weighted average interest rate of loans		11.25%
Commercial: | Commercial and industrial | Combination - Term Extension, Interest Rate Reduction, and Interest Forgiveness | Minimum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Weighted average interest rate of loans		7.50%
Commercial: | Commercial real estate | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 116.0	$ 42.0
% of Total Class	0.80%	0.30%
Weighted average life of loans	1 year 6 months	1 year
Commercial: | Commercial real estate | Combination - Term Extension, Interest Rate Reduction, and Interest Deferrals
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 0.0	$ 16.0
% of Total Class	0.00%	0.10%
Weighted average life of loans		1 year
Decrease from loan modification		$ 1.0
Commercial: | Commercial real estate | Combination - Term Extension, Interest Rate Reduction, and Interest Deferrals | Maximum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Weighted average interest rate of loans		8.65%
Commercial: | Commercial real estate | Combination - Term Extension, Interest Rate Reduction, and Interest Deferrals | Minimum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Weighted average interest rate of loans		8.00%