DERIVATIVE ASSETS AND DERIVATIVE LIABILITIES, Derivative Gain (Loss) Recognized in AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate (cash flow hedges)	$ (2)	$ 6
Total gains/(losses) included in AOCI, net of taxes	(12)	63
Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate (cash flow hedges)	(2)	6
Foreign exchange
Derivative Instruments, Gain (Loss) [Line Items]
Foreign exchange (net investment hedges)	$ (10)	$ 57