Financial Instruments (Currency Price Risk Management Instruments) (Details) - Forward Exchange Contracts - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Derivative [Line Items]
US$ Notional	$ 5,163.9	$ 4,302.5
Years Average Maturity	9 months 18 days	7 months 6 days
Designated as Hedging Instrument | Cash Flow Hedges
Derivative [Line Items]
US$ Notional	$ 2,842.1	$ 2,418.2
Years Average Maturity	6 months	6 months
Designated as Hedging Instrument | Net Investment Hedges
Derivative [Line Items]
US$ Notional	$ 636.6	$ 830.8
Years Average Maturity	3 years 9 months 18 days	10 months 24 days
Not Designated as Hedging Instrument
Derivative [Line Items]
US$ Notional	$ 1,685.2	$ 1,053.5
Years Average Maturity	3 months 18 days	7 months 6 days