VARIABLE INTEREST ENTITIES, Primary Beneficiary - Aggregate Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2024	Sep. 30, 2023
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Aggregate assets	$ 80,628	$ 78,360
Aggregate liabilities	69,438	68,173
Variable Interest Entity, Primary Beneficiary
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Aggregate assets	166	71
Aggregate liabilities	93	26
Variable Interest Entity, Primary Beneficiary | LIHTC funds
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Aggregate assets	139	51
Aggregate liabilities	66	6
Variable Interest Entity, Primary Beneficiary | Restricted Stock Trust Fund
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Aggregate assets	27	20
Aggregate liabilities	$ 27	$ 20