VARIABLE INTEREST ENTITIES - Schedule of Variable Interest Entities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Variable Interest Entity [Line Items]
Total assets	$ 217,836	$ 213,758
Liabilities	195,988	192,503
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Total assets	2,099	2,052
Variable Interest Entity, Not Primary Beneficiary | Total tax credit equity investments
Variable Interest Entity [Line Items]
Total assets	1,945	1,890
Variable Interest Entity, Not Primary Beneficiary | Affordable housing tax credit investments
Variable Interest Entity [Line Items]
Total assets	1,942	1,887
Variable Interest Entity, Not Primary Beneficiary | Other tax credit equity investments
Variable Interest Entity [Line Items]
Total assets	3	3
Variable Interest Entity, Not Primary Beneficiary | Other unconsolidated investments
Variable Interest Entity [Line Items]
Total assets	154	162
Variable Interest Entity, Not Primary Beneficiary | Commitments to tax credit investments
Variable Interest Entity [Line Items]
Liabilities	$ 982	$ 947