DERIVATIVES - Schedule of Fair Value Hedges (Details) - Interest rate swap - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Interest expense - long-term borrowed funds
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	$ (1)	$ (19)	$ 0	$ (71)
Hedged item	1	19	0	70
Interest and fees on other loans held for sale
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	0	18	0	15
Hedged item	0	(19)	0	(15)
Interest income - investment securities
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	16	0	28	29
Hedged item	$ (16)	$ 0	$ (28)	$ (29)