v3.26.1
DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Derivative Gain (Loss) Recognized/Reclassified) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of gain/(loss) reclassified from AOCI into income $ 13 $ (19)
Loss to be reclassified within the next 12 months into interest income 42 54
Deferred losses 27  
Derivatives designated as accounting hedges:    
Derivative Instruments, Gain (Loss) [Line Items]    
Effective portion of derivative gain/(loss) deferred in AOCI (29) 6
Amount of gain/(loss) reclassified from AOCI into income (11) (19)
Interest on fair value hedges 3 11
Derivatives designated as accounting hedges: | Cash Flow Hedging    
Derivative Instruments, Gain (Loss) [Line Items]    
Terminated or redesignated, unamortized basis adjustments, debt 30 38
Terminated or redesignated, unamortized basis adjustments, assets 2 3
Derivatives designated as accounting hedges: | Cash Flow Hedging | Hedges of floating-rate assets    
Derivative Instruments, Gain (Loss) [Line Items]    
Effective portion of derivative gain/(loss) deferred in AOCI (29) 6
Amount of gain/(loss) reclassified from AOCI into income (11) (20)
Interest on fair value hedges 0 0
Derivatives designated as accounting hedges: | Cash Flow Hedging | Hedges of floating-rate liabilities    
Derivative Instruments, Gain (Loss) [Line Items]    
Effective portion of derivative gain/(loss) deferred in AOCI 0 0
Amount of gain/(loss) reclassified from AOCI into income 0 1
Interest on fair value hedges 0 0
Derivatives designated as accounting hedges: | Fair Value Hedging | Hedges of fixed-rate assets    
Derivative Instruments, Gain (Loss) [Line Items]    
Effective portion of derivative gain/(loss) deferred in AOCI 0 0
Amount of gain/(loss) reclassified from AOCI into income 0 0
Interest on fair value hedges 5 13
Derivatives designated as accounting hedges: | Fair Value Hedging | Hedges of fixed-rate liabilities    
Derivative Instruments, Gain (Loss) [Line Items]    
Effective portion of derivative gain/(loss) deferred in AOCI 0 0
Amount of gain/(loss) reclassified from AOCI into income 0 0
Interest on fair value hedges $ (2) $ (2)