DERIVATIVES - Effect of Customer Derivatives and Economic Hedges on Net Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	$ 38	$ (49)	$ 87	$ (52)
Economic hedges \| Customer interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	(123)	70	(240)	235
Economic hedges \| Derivatives hedging interest rate risk
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	136	(62)	262	(219)
Economic hedges \| Customer foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	(63)	319	(151)	417
Economic hedges \| Derivatives hedging foreign exchange risk
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	88	(399)	206	(530)
Economic hedges \| Customer commodity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	(268)	(302)	41	41
Economic hedges \| Derivatives hedging commodity price risk
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	274	307	(26)	(29)
Economic hedges \| Residential loan commitments
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	0	3	(11)	9
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	(5)	(1)	14	(14)
Economic hedges \| Derivative contracts used to hedge residential MSRs
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	(14)	5	(22)	27
Economic hedges \| Derivative contracts used to hedge equity price risk
Derivative Instruments, Gain (Loss) [Line Items]
Amounts recognized in noninterest income	$ 13	$ 11	$ 14	$ 11