DERIVATIVE ASSETS AND DERIVATIVE LIABILITIES, Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Sep. 30, 2023
Derivative [Line Items]
Gain (loss) excluded from assessment of hedge effectiveness	$ 0	$ 0	$ 0	$ 0
Amount of interest expense expected to reclassify from AOCI	28,000,000		28,000,000
Derivative liabilities	354,000,000		354,000,000		$ 490,000,000
Credit Risk Contract
Derivative [Line Items]
Derivative liabilities	$ 2,000,000		$ 2,000,000		$ 3,000,000
Bank
Derivative [Line Items]
Maximum length of time hedged in cash flow hedge (in years)			3 years