Financial Instruments (Currency Price Risk Management Instruments) (Details) - Forward exchange contracts - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Mar. 31, 2024	Sep. 30, 2023
Derivative [Line Items]
US$ Notional	$ 6,238.4	$ 6,036.6
Years Average Maturity	9 months 18 days	10 months 24 days
Designated as hedging instrument \| Cash flow hedges
Derivative [Line Items]
US$ Notional	$ 4,576.1	$ 4,463.2
Years Average Maturity	7 months 6 days	8 months 12 days
Designated as hedging instrument \| Net investment hedges
Derivative [Line Items]
US$ Notional	$ 884.4	$ 864.0
Years Average Maturity	2 years	2 years 6 months
Not designated as hedging instrument
Derivative [Line Items]
US$ Notional	$ 777.9	$ 709.4
Years Average Maturity	3 months 18 days	3 months 18 days

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480237/815-40-50-5

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-1A

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