v3.26.1
ALLOWANCE FOR CREDIT LOSSES ON LOANS AND LEASES - Schedule of Changes in Allowance for Credit Losses (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period $ 439.0    
Charge- Offs (22.9)   $ (84.7)
Provision for Credit Losses 18.5 $ 17.5  
Balance at End of Period 443.0   439.0
Unfunded loan commitment      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 20.1 21.4 21.4
Charge- Offs 0.0 0.0  
Recoveries 0.0 0.0  
Net (Charge- Offs) Recoveries 0.0 0.0  
Provision for Credit Losses (0.9) (1.1)  
Balance at End of Period 19.2 20.3 20.1
Total commercial loans and leases      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 305.4 279.7 279.7
Charge- Offs (20.6) (13.1)  
Recoveries 6.4 3.2  
Net (Charge- Offs) Recoveries (14.2) (9.9)  
Provision for Credit Losses 15.0 19.4  
Balance at End of Period 306.2 289.2 305.4
Total commercial loans and leases | Commercial real estate      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 175.9 166.9 166.9
Charge- Offs (8.3) (7.6) (30.0)
Recoveries 0.2 0.4  
Net (Charge- Offs) Recoveries (8.1) (7.2)  
Provision for Credit Losses (2.1) 13.7  
Balance at End of Period 165.7 173.4 175.9
Total commercial loans and leases | Commercial and industrial      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 98.9 85.6 85.6
Charge- Offs (9.2) (4.3) (37.9)
Recoveries 5.9 2.5  
Net (Charge- Offs) Recoveries (3.3) (1.8)  
Provision for Credit Losses 14.1 4.8  
Balance at End of Period 109.7 88.6 98.9
Total commercial loans and leases | Commercial leases      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 26.2 22.9 22.9
Charge- Offs (2.0) (0.1) (0.2)
Recoveries 0.0 0.0  
Net (Charge- Offs) Recoveries (2.0) (0.1)  
Provision for Credit Losses 2.1 0.0  
Balance at End of Period 26.3 22.8 26.2
Total commercial loans and leases | Other      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 4.4 4.3 4.3
Charge- Offs (1.1) (1.1) (4.7)
Recoveries 0.3 0.3  
Net (Charge- Offs) Recoveries (0.8) (0.8)  
Provision for Credit Losses 0.9 0.9  
Balance at End of Period 4.5 4.4 4.4
Total commercial loans and leases | Unfunded loan commitment      
Allowance for Loan and Lease Losses [Roll Forward]      
Provision for Credit Losses (0.9) (1.1)  
Total consumer loans      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 134.1 143.1 143.1
Charge- Offs (2.3) (3.3)  
Recoveries 0.6 0.7  
Net (Charge- Offs) Recoveries (1.7) (2.6)  
Provision for Credit Losses 4.4 (0.8)  
Balance at End of Period 136.8 139.7 134.1
Total consumer loans | Direct installment      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 25.7 29.1 29.1
Charge- Offs (0.2) (0.4) (0.9)
Recoveries 0.1 0.1  
Net (Charge- Offs) Recoveries (0.1) (0.3)  
Provision for Credit Losses 0.2 (0.7)  
Balance at End of Period 25.8 28.1 25.7
Total consumer loans | Residential mortgages      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 92.4 95.9 95.9
Charge- Offs (0.4) (0.4) (2.4)
Recoveries 0.0 0.1  
Net (Charge- Offs) Recoveries (0.4) (0.3)  
Provision for Credit Losses 3.0 (1.5)  
Balance at End of Period 95.0 94.1 92.4
Total consumer loans | Indirect installment      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 9.0 9.5 9.5
Charge- Offs (1.5) (2.2) (7.6)
Recoveries 0.4 0.4  
Net (Charge- Offs) Recoveries (1.1) (1.8)  
Provision for Credit Losses 1.1 1.5  
Balance at End of Period 9.0 9.2 9.0
Total consumer loans | Consumer lines of credit      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 7.0 8.6 8.6
Charge- Offs (0.2) (0.3) (1.0)
Recoveries 0.1 0.1  
Net (Charge- Offs) Recoveries (0.1) (0.2)  
Provision for Credit Losses 0.1 (0.1)  
Balance at End of Period 7.0 8.3 7.0
Allowance for credit losses on loans and leases      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 439.5 422.8 422.8
Charge- Offs (22.9) (16.4)  
Recoveries 7.0 3.9  
Net (Charge- Offs) Recoveries (15.9) (12.5)  
Provision for Credit Losses 19.4 18.6  
Balance at End of Period 443.0 428.9 439.5
Allowance for credit losses on loans and leases and allowance for unfunded loan commitments      
Allowance for Loan and Lease Losses [Roll Forward]      
Balance at Beginning of Period 459.6 444.2 444.2
Charge- Offs (22.9) (16.4)  
Recoveries 7.0 3.9  
Net (Charge- Offs) Recoveries (15.9) (12.5)  
Provision for Credit Losses 18.5 17.5  
Balance at End of Period $ 462.2 $ 449.2 $ 459.6