VARIABLE INTEREST ENTITIES, Not the Primary Beneficiary - Aggregate Assets, Liabilities Exposure to Loss (Details) - USD ($) $ in Millions	Sep. 30, 2022	Sep. 30, 2021
Variable Interest Entity [Line Items]
Aggregate assets	$ 80,951	$ 61,891
Aggregate liabilities	71,519	53,588
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Aggregate assets	10,088	14,869
Aggregate liabilities	3,133	2,482
Our risk of loss	234	163
Variable Interest Entity, Not Primary Beneficiary | LIHTC funds
Variable Interest Entity [Line Items]
Aggregate assets	7,752	7,032
Aggregate liabilities	2,584	2,280
Our risk of loss	136	71
Variable Interest Entity, Not Primary Beneficiary | Private Equity Interests
Variable Interest Entity [Line Items]
Aggregate assets	2,177	7,318
Aggregate liabilities	448	47
Our risk of loss	90	82
Variable Interest Entity, Not Primary Beneficiary | Other
Variable Interest Entity [Line Items]
Aggregate assets	159	519
Aggregate liabilities	101	155
Our risk of loss	$ 8	$ 10