VARIABLE INTEREST ENTITIES, Primary Beneficiary - Aggregate Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2022	Sep. 30, 2021
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Total assets	$ 86,111	$ 61,891
Total liabilities	76,619	53,588
Variable Interest Entity, Primary Beneficiary
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Total assets	91	192
Total liabilities	34	71
Private Equity Interests | Variable Interest Entity, Primary Beneficiary
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Total assets		66
Total liabilities		4
LIHTC funds | Variable Interest Entity, Primary Beneficiary
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Total assets	67	111
Total liabilities	10	52
Restricted Stock Trust Fund | Variable Interest Entity, Primary Beneficiary
Variable interest entity, consolidated, aggregate assets and liabilities [Abstract]
Total assets	24	15
Total liabilities	$ 24	$ 15