FINANCIAL INSTRUMENTS - The Impact of Derivatives on Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in AOCI	$ 19	$ 3	$ (1)
Designated as Hedging Instrument | Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) reclassified from AOCI into income	4	(1)	1
Not Designated as Hedging Instrument | Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in income	0	(2)	1
Not Designated as Hedging Instrument | Other Income (expense)
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in income	$ 1	$ 2	$ 0