PENSION & POSTRETIREMENT PLANS - Schedule of Pension and Postretirement Plan Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Retirement Benefits [Abstract]
Service cost	$ 9	$ 12	$ 27	$ 36
Interest cost	55	54	165	162
Expected return on plan assets	(74)	(71)	(222)	(213)
Net amortization	(14)	(18)	(42)	(58)
Total	$ (24)	$ (23)	$ (72)	$ (73)