VARIABLE INTEREST ENTITIES VARIABLE INTEREST ENTITIES, Not the Primary Beneficiary - Aggregate Assets, Liabilities Exposure to Loss (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Variable Interest Entity [Line Items]
Aggregate assets	$ 47,482	$ 38,830
Aggregate liabilities	40,306	32,187
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Aggregate assets	14,481	12,523
Aggregate liabilities	2,225	2,453
Our risk of loss	139	131
Private Equity Interests | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Aggregate assets	7,738	6,317
Aggregate liabilities	96	117
Our risk of loss	67	63
LIHTC funds | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Aggregate assets	6,516	6,001
Aggregate liabilities	1,993	2,221
Our risk of loss	66	64
Other | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Aggregate assets	227	205
Aggregate liabilities	136	115
Our risk of loss	$ 6	$ 4