VARIABLE INTEREST ENTITIES - Schedule of Affordable Housing Tax Credit Investments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Variable Interest Entity
Income tax expense	$ (118)	$ (88)	$ (213)	$ (184)
Noninterest income	600	553	1,144	1,070
Net income	436	392	809	726
Variable Interest Entity, Not Primary Beneficiary | Net Income (Loss) Attributable To Parent, Net Benefit
Variable Interest Entity
Net income	24	28	50	47
Variable Interest Entity, Not Primary Beneficiary | Net benefit (expense) included in Income tax expense
Variable Interest Entity
Income tax expense	26	29	53	50
Variable Interest Entity, Not Primary Beneficiary | Tax credits recognized
Variable Interest Entity
Income tax expense	104	94	210	191
Variable Interest Entity, Not Primary Beneficiary | Other tax benefits recognized
Variable Interest Entity
Income tax expense	26	24	49	47
Variable Interest Entity, Not Primary Beneficiary | Amortization
Variable Interest Entity
Income tax expense	(104)	(89)	(206)	(188)
Variable Interest Entity, Not Primary Beneficiary | Net benefit (expense) included in Noninterest income
Variable Interest Entity
Noninterest income	(2)	(1)	(3)	(3)
Variable Interest Entity, Not Primary Beneficiary | Other income
Variable Interest Entity
Noninterest income	2	2	4	3
Variable Interest Entity, Not Primary Beneficiary | Allocated income (loss) on investments
Variable Interest Entity
Noninterest income	$ (4)	$ (3)	$ (7)	$ (6)