v3.26.1
Income Taxes (Details) - USD ($)
$ in Millions
3 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Income Tax Contingency [Line Items]      
Effective tax rate (as a percent) 21.60% 21.40%  
Combined federal and state statutory tax rate (as a percent) 24.20%    
Valuation allowance $ 5.0   $ 5.0
First Niagara Bank, N.A.      
Income Tax Contingency [Line Items]      
Allocated bad debt deductions 92.0    
Key Corp      
Income Tax Contingency [Line Items]      
Unrecognized tax benefits 3.0    
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssets      
Income Tax Contingency [Line Items]      
Net deferred tax assets $ 1,200.0   $ 1,200.0