DERIVATIVE ASSETS AND DERIVATIVE LIABILITIES, Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2022
Derivative [Line Items]
Gain (loss) excluded from assessment of hedge effectiveness	$ 0	$ 0	$ 0	$ 0
Amount of interest expense expected to be reclassified out of AOCI to earnings within the next 12 months	36,000,000		36,000,000
Derivative liabilities	393,000,000		393,000,000		$ 530,000,000
Credit Risk Contract
Derivative [Line Items]
Derivative liabilities	$ 3,000,000		$ 3,000,000		$ 8,000,000
Bank
Derivative [Line Items]
Maximum length of time hedged in cash flow hedge			4 years