LONG-TERM DEBT - Capital Leases (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Capital Leased Assets [Line Items]
Capital lease term	1 year
Future Minimum Payments Due by Fiscal Year Maturity
Capital lease obligation, Total	$ 8
Capital lease obligation, 2020	2
Capital lease obligation, 2021	3
Capital lease obligation, 2022	2
Capital lease obligation, 2023	1
Capital lease obligation, 2024	0
Capital lease obligation, Thereafter	0
Less: amounts representing interest, Total	(1)
Less: amounts representing interest, 2020	(1)
Less: amounts representing interest, 2021	0
Less: amounts representing interest, 2022	0
Less: amounts representing interest, 2023	0
Less: amounts representing interest, 2024	0
Less: amounts representing interest, Thereafter	0
Principal on capital lease, Total	7
Principal on capital lease, 2020	1
Principal on capital lease, 2021	3
Principal on capital lease, 2022	2
Principal on capital lease, 2023	1
Principal on capital lease, 2024	0
Principal on capital lease, Thereafter	0
Other Capital Lease Arrangements
Capital Leased Assets [Line Items]
Amount outstanding under capital leases	$ 7	$ 7

Capital Leases, Future Minimum Payments, Interest Included In Payments, Due In Five Years

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Capital Leases, Future Minimum Payments, Interest Included In Payments, Due In Four Years

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Capital Leases, Future Minimum Payments, Interest Included In Payments, Due In Three Years

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Capital Leases, Future Minimum Payments, Interest Included In Payments, Due In Two Years

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Capital Leases, Future Minimum Payments, Interest Included In Payments, Next Twelve Months

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Capital Leases, Future Minimum Payments, Present Value Of Net Minimum Payments, Due In Three Years

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Capital lease term.

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Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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Amount of minimum lease payments for capital leases.

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Amount of minimum lease payments for capital leases due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount necessary to reduce net minimum lease payments to present value for capital leases.

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Present value of minimum lease payments for capital leases net of executory costs, including amounts paid by the lessee to the lessor for insurance, maintenance and taxes.

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