VARIABLE INTEREST ENTITIES - Schedule of Affordable Housing Tax Credit Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Variable Interest Entity [Line Items]
Income tax expense	$ (379)	$ (422)	$ (582)
Noninterest income	2,176	1,983	2,009
Net income	1,509	1,608	2,073
Variable Interest Entity, Not Primary Beneficiary | Net Income (Loss) Attributable To Parent, Net Benefit
Variable Interest Entity [Line Items]
Net income	101	80	48
Variable Interest Entity, Not Primary Beneficiary | Net benefit (expense) included in income tax expense
Variable Interest Entity [Line Items]
Income tax expense	109	85	48
Variable Interest Entity, Not Primary Beneficiary | Tax credits recognized
Variable Interest Entity [Line Items]
Income tax expense	379	334	236
Variable Interest Entity, Not Primary Beneficiary | Other tax benefits recognized
Variable Interest Entity [Line Items]
Income tax expense	93	71	59
Variable Interest Entity, Not Primary Beneficiary | Amortization
Variable Interest Entity [Line Items]
Income tax expense	(363)	(320)	(247)
Variable Interest Entity, Not Primary Beneficiary | Net benefit (expense) included in noninterest income
Variable Interest Entity [Line Items]
Noninterest income	(8)	(5)	0
Variable Interest Entity, Not Primary Beneficiary | Other income
Variable Interest Entity [Line Items]
Noninterest income	4	5	0
Variable Interest Entity, Not Primary Beneficiary | Allocated income (loss) on investments
Variable Interest Entity [Line Items]
Noninterest income	$ (12)	$ (10)	$ 0