VARIABLE INTEREST ENTITIES - Schedule of Affordable Housing Tax Credit Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Variable Interest Entity [Line Items]
Income tax expense	$ (497)	$ (379)	$ (422)
Noninterest income	2,394	2,176	1,983
Net income	1,831	1,509	1,608
Variable Interest Entity, Not Primary Beneficiary | Net Income (Loss) Attributable To Parent, Net Benefit
Variable Interest Entity [Line Items]
Net income	96	101	80
Variable Interest Entity, Not Primary Beneficiary | Net benefit (expense) included in income tax expense
Variable Interest Entity [Line Items]
Income tax expense	102	109	85
Variable Interest Entity, Not Primary Beneficiary | Tax credits recognized
Variable Interest Entity [Line Items]
Income tax expense	410	379	334
Variable Interest Entity, Not Primary Beneficiary | Other tax benefits recognized
Variable Interest Entity [Line Items]
Income tax expense	98	93	71
Variable Interest Entity, Not Primary Beneficiary | Amortization
Variable Interest Entity [Line Items]
Income tax expense	(406)	(363)	(320)
Variable Interest Entity, Not Primary Beneficiary | Net benefit (expense) included in noninterest income
Variable Interest Entity [Line Items]
Noninterest income	(6)	(8)	(5)
Variable Interest Entity, Not Primary Beneficiary | Other income
Variable Interest Entity [Line Items]
Noninterest income	6	4	5
Variable Interest Entity, Not Primary Beneficiary | Allocated income (loss) on investments
Variable Interest Entity [Line Items]
Noninterest income	$ (12)	$ (12)	$ (10)