Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Sep. 30, 2014
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 207	$ 247
Short-term debt	5	7
Long-term debt	945	965
Carrying Value \| Foreign exchange forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Foreign exchange forward contracts (asset)	5	2
Carrying Value \| Foreign currency option contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term foreign currency option contracts (asset)	2	2
Long-term foreign currency option contracts (asset)	2	1
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	207	247
Short-term debt	5	7
Long-term debt	1,131	1,143
Fair Value \| Foreign exchange forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Foreign exchange forward contracts (asset)	5	2
Fair Value \| Foreign currency option contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term foreign currency option contracts (asset)	2	2
Long-term foreign currency option contracts (asset)	$ 2	$ 1

Fair value, after the effects of master netting arrangements, of a 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. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a 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, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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- Definition

Fair value, after the effects of master netting arrangements, of a 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, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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