Financial Instruments (Schedule of Outstanding Currency Price Risk Management Instruments) (Details) - Forward Exchange Contracts - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Jun. 30, 2019	Sep. 30, 2018
Derivative [Line Items]
US$ Notional	$ 4,130.9	$ 4,682.7
Years Average Maturity	7 months 6 days	8 months 12 days
Designated as Hedging Instrument | Cash Flow Hedges
Derivative [Line Items]
US$ Notional	$ 2,656.2	$ 2,489.1
Years Average Maturity	4 months 24 days	4 months 24 days
Designated as Hedging Instrument | Net Investment Hedges
Derivative [Line Items]
US$ Notional	$ 553.0	$ 457.5
Years Average Maturity	1 year	1 year 8 months 12 days
Not Designated as Hedging Instrument
Derivative [Line Items]
US$ Notional	$ 921.7	$ 1,736.1
Years Average Maturity	10 months 24 days	9 months 18 days