Financial Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Sep. 30, 2018
Derivative [Line Items]
Total Derivatives, Assets	$ 148.4	$ 146.1
Total Derivatives, Liabilities	70.2	94.1
Designated as Hedging Instrument
Derivative [Line Items]
Total Derivatives, Assets	122.5	117.7
Total Derivatives, Liabilities	40.2	55.5
Designated as Hedging Instrument | Other Receivables | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	34.7	24.9
Designated as Hedging Instrument | Other Receivables | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	23.0	24.3
Designated as Hedging Instrument | Other Noncurrent Assets | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	25.7	19.8
Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	39.1	48.7
Designated as Hedging Instrument | Accrued Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	27.9	37.0
Designated as Hedging Instrument | Accrued Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	1.3	2.3
Designated as Hedging Instrument | Other Noncurrent Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	1.9	4.6
Designated as Hedging Instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	9.1	11.6
Not Designated as Hedging Instrument
Derivative [Line Items]
Total Derivatives, Assets	25.9	28.4
Total Derivatives, Liabilities	30.0	38.6
Not Designated as Hedging Instrument | Other Receivables | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	0.9	7.9
Not Designated as Hedging Instrument | Other Receivables | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	3.6	4.0
Not Designated as Hedging Instrument | Other Noncurrent Assets | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	21.4	16.2
Not Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	0.0	0.3
Not Designated as Hedging Instrument | Accrued Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	1.1	14.9
Not Designated as Hedging Instrument | 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	28.9	23.7
Not Designated as Hedging Instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	$ 0.0	$ 0.0