COMMITMENTS AND CONTINGENCIES - Schedule of Outstanding Off-balance sheet Arrangements (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Other Commitments [Line Items]
Commitment amount	$ 102,680	$ 95,413
Commitments to extend credit
Other Commitments [Line Items]
Commitment amount	100,650	93,460
Letters of credit
Other Commitments [Line Items]
Commitment amount	1,901	1,845
Loans sold with recourse
Other Commitments [Line Items]
Commitment amount	89	93
Risk participation agreements
Other Commitments [Line Items]
Commitment amount	29	1
Other commitments
Other Commitments [Line Items]
Commitment amount	$ 11	$ 14