VARIABLE INTEREST ENTITIES - Schedule of Affordable Housing Tax Credit Investments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Variable Interest Entity
Income tax expense	$ (88)	$ (134)	$ (184)	$ (287)
Noninterest income	553	506	1,070	991
Net income	392	478	726	989
Variable Interest Entity, Not Primary Beneficiary | Net Income (Loss) Attributable To Parent, Net Benefit
Variable Interest Entity
Net income	28	21	47	43
Variable Interest Entity, Not Primary Beneficiary | Net benefit (expense) included in income tax expense
Variable Interest Entity
Income tax expense	29	22	50	46
Variable Interest Entity, Not Primary Beneficiary | Tax credits recognized
Variable Interest Entity
Income tax expense	94	87	191	174
Variable Interest Entity, Not Primary Beneficiary | Other tax benefits recognized
Variable Interest Entity
Income tax expense	24	20	47	38
Variable Interest Entity, Not Primary Beneficiary | Amortization
Variable Interest Entity
Income tax expense	(89)	(85)	(188)	(166)
Variable Interest Entity, Not Primary Beneficiary | Net benefit (expense) included in noninterest income
Variable Interest Entity
Noninterest income	(1)	(1)	(3)	(3)
Variable Interest Entity, Not Primary Beneficiary | Other income
Variable Interest Entity
Noninterest income	2	2	3	3
Variable Interest Entity, Not Primary Beneficiary | Allocated income (loss) on investments
Variable Interest Entity
Noninterest income	$ (3)	$ (3)	$ (6)	$ (6)