FAIR VALUE, Investments in Private Equity Measured at Net Asset Value Per Share (Details) - Private equity investments - Recurring - USD ($) $ in Millions	Jun. 30, 2023	Sep. 30, 2022
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Private equity investments measured at NAV	$ 100	$ 90
Private equity investments not measured at NAV	7	5
Total private equity investments	107	95
Unfunded commitment	$ 36	$ 39