Financial Instruments (Fair Value and Balance Sheet Location of Derivatives) (Details) - USD ($) $ in Millions	Mar. 31, 2026	Sep. 30, 2025
Derivative [Line Items]
Total Derivatives, Assets	$ 328.4	$ 244.4
Total Derivatives, Liabilities	182.5	93.6
Designated as hedging instrument
Derivative [Line Items]
Total Derivatives, Assets	324.1	212.1
Total Derivatives, Liabilities	149.3	48.9
Designated as hedging instrument | Other Receivables and Current Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	57.4	50.7
Designated as hedging instrument | Other Receivables and Current Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	3.2	13.1
Designated as hedging instrument | Other Noncurrent Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	15.5	10.1
Designated as hedging instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	248.0	138.2
Designated as hedging instrument | Payables and Accrued Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	63.2	21.4
Designated as hedging instrument | Payables and Accrued Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	2.0	0.3
Designated as hedging instrument | Other Noncurrent Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	2.4	3.4
Designated as hedging instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	81.7	23.8
Not designated as hedging instrument
Derivative [Line Items]
Total Derivatives, Assets	4.3	32.3
Total Derivatives, Liabilities	33.2	44.7
Not designated as hedging instrument | Other Receivables and Current Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	4.3	17.8
Not designated as hedging instrument | Other Noncurrent Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	0.0	2.7
Not designated as hedging instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	0.0	11.8
Not designated as hedging instrument | Payables and Accrued Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	4.4	14.2
Not designated as hedging instrument | Other Noncurrent Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	28.2	30.5
Not designated as hedging instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	$ 0.6	$ 0.0