Financial Instruments (Fair Value and Balance Sheet Location of Derivatives) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020
Derivative [Line Items]
Total Derivatives, Assets	$ 146.6	$ 143.3
Total Derivatives, Liabilities	154.1	85.6
Designated as Hedging Instrument
Derivative [Line Items]
Total Derivatives, Assets	128.2	110.9
Total Derivatives, Liabilities	136.6	57.6
Designated as Hedging Instrument | Other Receivables and Current Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	97.2	51.1
Designated as Hedging Instrument | Other Receivables and Current Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	13.1	14.7
Designated as Hedging Instrument | Other Noncurrent Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	3.3	0.8
Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	14.6	44.3
Designated as Hedging Instrument | Accrued Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	42.8	22.5
Designated as Hedging Instrument | Accrued Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	7.2	0.4
Designated as Hedging Instrument | Other Noncurrent Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	53.9	33.0
Designated as Hedging Instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	32.7	1.7
Not Designated as Hedging Instrument
Derivative [Line Items]
Total Derivatives, Assets	18.4	32.4
Total Derivatives, Liabilities	17.5	28.0
Not Designated as Hedging Instrument | Other Receivables and Current Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	18.4	31.7
Not Designated as Hedging Instrument | Other Noncurrent Assets | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Assets	0.0	0.0
Not Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	0.0	0.7
Not Designated as Hedging Instrument | Accrued Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	17.2	28.0
Not Designated as Hedging Instrument | Other Noncurrent Liabilities | Forward exchange contracts
Derivative [Line Items]
Total Derivatives, Liabilities	0.2	0.0
Not Designated as Hedging Instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	$ 0.1	$ 0.0