Financial Instruments (Schedule Of Fair Values Of Derivative Contracts Outstanding) (Details) - Fair Value, Level 2 [Member] - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Financial Instruments [Line Items]
Fair value of long-term debt	$ 6,800	$ 7,300
Fair value of long-term debt compared with carrying value	485	629
Foreign Currency [Member]
Financial Instruments [Line Items]
Fair value of derivative assets	36	26
Fair value of derivative liabilities	6	25
Commodity [Member]
Financial Instruments [Line Items]
Fair value of derivative assets	12	11
Fair value of derivative liabilities	$ 6	$ 0

Fair value, before effects of master netting arrangements, of a financial liability or 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 liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant