VARIABLE INTEREST ENTITIES, Not the Primary Beneficiary - Aggregate Assets, Liabilities Exposure to Loss (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Variable Interest Entity [Line Items]
Aggregate assets	$ 82,992	$ 78,360
Aggregate liabilities	71,325	68,173
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Aggregate assets	12,077	11,243
Aggregate liabilities	4,098	3,703
Our risk of loss	282	217
Variable Interest Entity, Not Primary Beneficiary | LIHTC funds
Variable Interest Entity [Line Items]
Aggregate assets	9,049	8,451
Aggregate liabilities	3,079	2,964
Our risk of loss	116	113
Variable Interest Entity, Not Primary Beneficiary | Private Equity Interests
Variable Interest Entity [Line Items]
Aggregate assets	2,824	2,591
Aggregate liabilities	873	655
Our risk of loss	102	101
Variable Interest Entity, Not Primary Beneficiary | Other
Variable Interest Entity [Line Items]
Aggregate assets	204	201
Aggregate liabilities	146	84
Our risk of loss	$ 64	$ 3