DERIVATIVES - Effect of Customer Derivatives and Economic Hedges on Net Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	$ 49	$ (3)
Economic hedges | Customer interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	(117)	165
Economic hedges | Derivatives hedging interest rate risk
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	126	(157)
Economic hedges | Customer foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	(88)	98
Economic hedges | Derivatives hedging foreign exchange risk
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	118	(131)
Economic hedges | Customer commodity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	309	343
Economic hedges | Derivatives hedging commodity price risk
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	(300)	(336)
Economic hedges | Residential loan commitments
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	(11)	6
Economic hedges | Derivatives hedging residential loan commitments and mortgage loans held for sale, at fair value
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	19	(13)
Economic hedges | Derivative contracts used to hedge residential MSRs
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	(8)	22
Economic hedges | Derivative contracts used to hedge equity price risk
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	$ 1	$ 0