VARIABLE INTEREST ENTITIES VARIABLE INTEREST ENTITIES, Not the Primary Beneficiary - Aggregate Assets, Liabilities Exposure to Loss (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Variable Interest Entity [Line Items]
Aggregate assets	$ 61,891	$ 47,482
Aggregate liabilities	53,588	40,306
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Aggregate assets	14,869	14,481
Aggregate liabilities	2,482	2,225
Our risk of loss	163	139
Private Equity Interests | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Aggregate assets	7,318	7,738
Aggregate liabilities	47	96
Our risk of loss	82	67
LIHTC funds | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Aggregate assets	7,032	6,516
Aggregate liabilities	2,280	1,993
Our risk of loss	71	66
Other | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Aggregate assets	519	227
Aggregate liabilities	155	136
Our risk of loss	$ 10	$ 6