VARIABLE INTEREST ENTITIES, Primary Beneficiary - Aggregate Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2023	Sep. 30, 2022
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Total assets	$ 79,180	$ 80,951
Total liabilities	69,211	71,519
Variable Interest Entity, Primary Beneficiary
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Total assets	81	76
Total liabilities	32	23
Variable Interest Entity, Primary Beneficiary | LIHTC funds
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Total assets	55	59
Total liabilities	6	6
Variable Interest Entity, Primary Beneficiary | Restricted Stock Trust Fund
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Total assets	26	17
Total liabilities	$ 26	$ 17