Financial Instruments (Fair Value and Balance Sheet Location of Derivatives) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Sep. 30, 2019
Derivative [Line Items]
Total Derivatives, Assets	$ 273.2	$ 224.2
Total Derivatives, Liabilities	68.4	112.4
Designated as Hedging Instrument
Derivative [Line Items]
Total Derivatives, Assets	184.8	176.6
Total Derivatives, Liabilities	30.8	56.3
Designated as Hedging Instrument | Other Receivables and Current Assets | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	68.9	79.0
Designated as Hedging Instrument | Other Receivables and Current Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	35.6	24.8
Designated as Hedging Instrument | Other Noncurrent Assets | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	2.8	11.9
Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	77.5	60.9
Designated as Hedging Instrument | Accrued Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	16.0	53.8
Designated as Hedging Instrument | Accrued Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	0.0	1.1
Designated as Hedging Instrument | Other Noncurrent Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	14.8	0.7
Designated as Hedging Instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	0.0	0.7
Not Designated as Hedging Instrument
Derivative [Line Items]
Total Derivatives, Assets	88.4	47.6
Total Derivatives, Liabilities	37.6	56.1
Not Designated as Hedging Instrument | Other Receivables and Current Assets | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	88.4	38.7
Not Designated as Hedging Instrument | Other Noncurrent Assets | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	0.0	8.4
Not Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	0.0	0.5
Not Designated as Hedging Instrument | Accrued Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	37.6	36.3
Not Designated as Hedging Instrument | Other Noncurrent Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	0.0	19.8
Not Designated as Hedging Instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	$ 0.0	$ 0.0