v3.26.1
Derivatives and Hedging Activities - Derivative Instruments, Gain (Loss) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Income Statement Location [Axis]: us-gaap:InterestAndFeeIncomeLoansAndLeases | Loans HFI        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain/(Loss) on Swaps $ 15.0 $ (31.6) $ 24.9 $ (95.4)
Gain/(Loss) on Hedged Item (15.1) 31.6 (25.1) 95.5
Income Statement Location [Axis]: us-gaap:InterestExpenseSubordinatedNotesAndDebentures        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain/(Loss) on Swaps (6.9) 0.0 (4.6) 0.0
Gain/(Loss) on Hedged Item 6.9 0.0 4.6 0.0
Income Statement Location [Axis]: us-gaap:InterestIncomeSecuritiesTaxable | Investment securities - AFS        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain/(Loss) on Swaps 33.0 (38.4) 10.3 (38.4)
Gain/(Loss) on Hedged Item $ (31.9) $ 40.2 $ (8.3) $ 40.2