DERIVATIVE FINANCIAL INSTRUMENTS - MSR Hedging Activities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Remaining maturity	1 year
Notional Value	$ 45,059		$ 44,024
Derivative used in Mortgage Banking Activities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, fair value, net	20		2
Notional Value	2,533		2,658
Trading liabilities	27		18
Trading gains (losses)	(10)	$ 15
Commitments to sell loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Commitments to sell residential real estate loans	$ 1,800		$ 1,200