STOCK-BASED COMPENSATION - Schedule of Cash Proceeds Received and Tax Benefit from Share-based Payment Awards, Options (Details) - Employee Stock Option - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash received for option exercises	$ 9	$ 14	$ 49
Intrinsic value of options exercised	14	15	27
Tax benefits related to option exercises	$ 3	$ 5	$ 4