PENSION AND POSTRETIREMENT PLANS - Schedule of Retirement Plans Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost (benefits earned during the period)	$ 17	$ 25	$ 49
Interest cost	169	164	99
Expected return on plan assets	(259)	(247)	(253)
Net amortization and other	(43)	(55)	102
Net periodic pension expense (income)	(116)	(113)	(3)
Defined contribution plans	130	111	124
Total retirement plans expense (income)	14	(2)	121
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost (benefits earned during the period)	20	20	25
Interest cost	49	50	33
Expected return on plan assets	(38)	(39)	(56)
Net amortization and other	6	18	3
Net periodic pension expense (income)	37	49	5
Defined contribution plans	70	49	52
Total retirement plans expense (income)	$ 107	$ 98	$ 57