VARIABLE INTEREST ENTITIES - Schedule of Affordable Housing Tax Credit Investments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Variable Interest Entity
Income tax expense	$ (88)	$ (119)	$ (272)	$ (406)
Noninterest income	532	492	1,602	1,483
Net income	382	430	1,108	1,419
Variable Interest Entity, Not Primary Beneficiary | Net Income (Loss) Attributable To Parent, Net Benefit
Variable Interest Entity
Net income	30	22	77	65
Variable Interest Entity, Not Primary Beneficiary | Net benefit (expense) included in income tax expense
Variable Interest Entity
Income tax expense	32	22	82	68
Variable Interest Entity, Not Primary Beneficiary | Tax credits recognized
Variable Interest Entity
Income tax expense	99	76	290	250
Variable Interest Entity, Not Primary Beneficiary | Other tax benefits recognized
Variable Interest Entity
Income tax expense	21	17	68	55
Variable Interest Entity, Not Primary Beneficiary | Amortization
Variable Interest Entity
Income tax expense	(88)	(71)	(276)	(237)
Variable Interest Entity, Not Primary Beneficiary | Net benefit (expense) included in noninterest income
Variable Interest Entity
Noninterest income	(2)	0	(5)	(3)
Variable Interest Entity, Not Primary Beneficiary | Other income
Variable Interest Entity
Noninterest income	1	1	4	4
Variable Interest Entity, Not Primary Beneficiary | Allocated income (loss) on investments
Variable Interest Entity
Noninterest income	$ (3)	$ (1)	$ (9)	$ (7)