Financial Instruments - Offsetting of Derivative Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2020	Sep. 30, 2019
Cross-currency swaps
Derivative Assets
Gross Amounts Recognized	$ 0	$ 10
Gross Amounts Offset	0	0
Net Amounts Reported	0	10
Derivative Liabilities
Gross Amounts Recognized	0	5
Gross Amounts Offset	0	0
Net Amounts Reported	0	5
Foreign exchange forward contracts
Derivative Liabilities
Gross Amounts Recognized	2	0
Gross Amounts Offset	0	0
Net Amounts Reported	$ 2	$ 0

Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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