Income Taxes (Schedule Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Period over which the amount of unrecognized tax benefits are not expected to significantly increase or decrease	12 months
Unrecognized tax benefits, beginning	$ 159	$ 158
Additions for current year tax positions	25	15
Additions for prior year tax positions	29	18
Reductions for prior year tax positions	(8)	(22)
Acquisitions and divestitures	0	4
Reductions for settlements with tax authorities	0	(5)
Reductions for expiration of statutes of limitations	(10)	(9)
Unrecognized tax benefits, ending	$ 195	$ 159

Period over which the amount of unrecognized tax benefits are not expected to significantly increase or decrease.

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- Definition

Unrecognized tax benefits, increase (decrease) resulting from acquisition/divestiture

+ References

No definition available.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
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- Definition

Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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- Definition

Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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