OPERATING CASH FLOWS AND OTHER SUPPLEMENTAL FINANCIAL INFORMATION - Schedule of Supplemental Disclosures (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Balance sheet data:
Allowance for doubtful accounts	$ 3	$ 4	$ 5
Statement of operations data:
Maintenance and repairs expense	55	52	46
Research, development and engineering expense	75	73	69
Depreciation expense	76	74	67
Rental expense	19	18	14
Interest income	4	3	3
Interest expense	(61)	(70)	(122)
Statement of cash flows data:
Interest payments, net of receipts	41	49	75
Income tax payments, net of refunds	64	33	22
Non-cash investing activities - capital asset additions from capital leases	$ 0	$ 4	$ 0