DERIVATIVE ASSETS AND DERIVATIVE LIABILITIES, Narrative (Details) - USD ($)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Derivative [Line Items]
Gain (loss) excluded from assessment of hedge effectiveness	$ 0	$ 0	$ 0
Amount of interest expense expected to reclassify from AOCI	35,000,000
Derivative liabilities	490,000,000	530,000,000
Credit Risk Contract
Derivative [Line Items]
Derivative liabilities	$ 3,000,000	$ 8,000,000
Bank
Derivative [Line Items]
Maximum length of time hedged in cash flow hedge	4 years