Financial Instruments (Fair Value and Balance Sheet Location of Derivatives) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Sep. 30, 2023
Derivative [Line Items]
Total Derivatives, Assets	$ 265.2	$ 394.1
Total Derivatives, Liabilities	152.5	211.4
Designated as hedging instrument
Derivative [Line Items]
Total Derivatives, Assets	256.4	383.8
Total Derivatives, Liabilities	148.2	206.8
Designated as hedging instrument | Other Receivables and Current Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	55.8	50.2
Designated as hedging instrument | Other Receivables and Current Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	7.2	13.0
Designated as hedging instrument | Other Noncurrent Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	9.0	19.8
Designated as hedging instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	184.4	300.8
Designated as hedging instrument | Payables and Accrued Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	66.7	94.1
Designated as hedging instrument | Payables and Accrued Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	0.0	0.0
Designated as hedging instrument | Other Noncurrent Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	16.3	25.7
Designated as hedging instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	65.2	87.0
Not designated as hedging instrument
Derivative [Line Items]
Total Derivatives, Assets	8.8	10.3
Total Derivatives, Liabilities	4.3	4.6
Not designated as hedging instrument | Other Receivables and Current Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	7.3	6.4
Not designated as hedging instrument | Other Receivables and Current Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	1.4	3.9
Not designated as hedging instrument | Other Noncurrent Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	0.1	0.0
Not designated as hedging instrument | Payables and Accrued Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	4.2	4.6
Not designated as hedging instrument | Payables and Accrued Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	0.0	0.0
Not designated as hedging instrument | Other Noncurrent Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	$ 0.1	$ 0.0