Financial Instruments (Currency Price Risk Management Instruments) (Details) - Forward exchange contracts - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Mar. 31, 2022	Sep. 30, 2021
Derivative [Line Items]
US$ Notional	$ 5,009.7	$ 4,795.8
Years Average Maturity	9 months 18 days	9 months 18 days
Designated as Hedging Instrument | Cash Flow Hedges
Derivative [Line Items]
US$ Notional	$ 3,882.1	$ 3,465.2
Years Average Maturity	7 months 6 days	7 months 6 days
Designated as Hedging Instrument | Net Investment Hedges
Derivative [Line Items]
US$ Notional	$ 616.8	$ 638.0
Years Average Maturity	2 years 6 months	3 years
Not Designated as Hedging Instrument
Derivative [Line Items]
US$ Notional	$ 510.8	$ 692.6
Years Average Maturity	2 months 12 days	1 month 6 days