v3.26.1
BORROWED FUNDS - Narrative (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Debt Instrument [Line Items]    
Principal balance $ 12,300 $ 11,300
Unamortized deferred issuance costs and/or discounts 70 71
Short-term borrowed funds 54 58
Available borrowing capacity 80,700  
Federal Home Loan Bank Advances and Letters of Credit | Secured Debt    
Debt Instrument [Line Items]    
Short-term borrowed funds 7,300 7,100
Federal Home Loan Bank advances    
Debt Instrument [Line Items]    
Available borrowing capacity $ 23,200 $ 22,100