Financial Instruments (Currency Price Risk Management Instruments) (Details) - Forward exchange contracts - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Jun. 30, 2025	Sep. 30, 2024
Derivative [Line Items]
US$ Notional	$ 6,107.8	$ 6,794.6
Years Average Maturity	1 year	9 months 18 days
Designated as hedging instrument | Cash flow hedges
Derivative [Line Items]
US$ Notional	$ 3,110.7	$ 4,003.2
Years Average Maturity	7 months 6 days	7 months 6 days
Designated as hedging instrument | Net investment hedges
Derivative [Line Items]
US$ Notional	$ 160.9	$ 911.4
Years Average Maturity	1 month 6 days	2 years 6 months
Not designated as hedging instrument
Derivative [Line Items]
US$ Notional	$ 2,836.2	$ 1,880.0
Years Average Maturity	1 year 4 months 24 days	3 months 18 days