INCOME TAXES, Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Line Items]
Amortization of investments accounted for under the proportional amortization method, statements of income location	Provision for income taxes	Provision for income taxes	Provision for income taxes
Unamortized equity investments accounted for under the proportional amortization method, location	Other assets
Deferred tax assets, net of valuation allowance	$ 971	$ 1,060
Cumulative undistributed earnings attributable to foreign subsidiaries	578
Current tax receivable	28	9
Current tax payable	0	17
Income tax penalties and interest accrued	14	12
Unrecognized tax benefits that would impact effective tax rate	41	35	$ 38
Decrease in unrecognized tax benefits is reasonably possible	22
Renewable energy tax credit investments
Income Tax Disclosure [Line Items]
Amortization of investments accounted for under the proportional amortization method	28	86	0
Tax credits related to investments accounted for under the proportional amortization method	28	81
Other tax benefits related to investments accounted for under the proportional amortization method		9
Remaining commitments related to investments accounted for under the proportional amortization method	63
Unamortized equity investments accounted for under the proportional amortization method	61
LIHTC investments
Income Tax Disclosure [Line Items]
Amortization of investments accounted for under the proportional amortization method	3	3	$ 0
Tax credits related to investments accounted for under the proportional amortization method	3	3
Other payables
Income Tax Disclosure [Line Items]
Net deferred tax liabilities	$ 4	$ 8