DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of Derivative Instruments Fair Value Hedges (Details) - Qualifying Hedges - Interest rate contracts - Fair Value Hedges - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net gain on fair value hedges	$ 1	$ (2)	$ 3	$ (3)
Deposits
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Recognized on derivatives	0	2	0	1
Recognized on hedged item	1	(3)	1	(2)
Borrowings
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Recognized on derivatives	0	4	0	(2)
Recognized on hedged item	$ 0	$ (5)	$ 2	$ 0