VARIABLE INTEREST ENTITIES - Schedule of Variable Interest Entities (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	$ 235,959	$ 229,698
Liabilities for commitments to fund tax credit investments	213,911	207,460
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	2,909	2,955
Variable Interest Entity, Not Primary Beneficiary | Total tax credit equity investments
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	2,710	2,761
Variable Interest Entity, Not Primary Beneficiary | Affordable housing tax credit investments
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	2,682	2,761
Variable Interest Entity, Not Primary Beneficiary | Other tax credit investments
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	28	0
Variable Interest Entity, Not Primary Beneficiary | Other unconsolidated investments
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	199	194
Variable Interest Entity, Not Primary Beneficiary | Commitments to tax credit investments
Variable Interest Entity [Line Items]
Liabilities for commitments to fund tax credit investments	$ 1,234	$ 1,321