BANK DEPOSITS, Bank Deposits by Insured and Uninsured (Details) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022
Deposits [Abstract]
FDIC-insured bank deposits	$ 48,344	$ 44,289
Bank deposits exceeding FDIC insurance limit	5,855	7,068
Total bank deposits	$ 54,199	$ 51,357
FDIC-insured bank deposits as a % of total bank deposits	89.00%	86.00%
Related Party Transaction [Line Items]
Bank deposits exceeding FDIC insurance limit	$ 5,855	$ 7,068
Related party
Deposits [Abstract]
Bank deposits exceeding FDIC insurance limit	764	770
Related Party Transaction [Line Items]
Bank deposits exceeding FDIC insurance limit	$ 764	$ 770