Financial Instruments (Currency Price Risk Management Instruments) (Details) - Forward exchange contracts - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2025	Sep. 30, 2025
Derivative [Line Items]
US$ Notional	$ 6,835.8	$ 6,668.0
Years Average Maturity	8 months 12 days	10 months 24 days
Designated as hedging instrument | Cash flow hedges
Derivative [Line Items]
US$ Notional	$ 4,094.9	$ 3,625.5
Years Average Maturity	4 months 24 days	7 months 6 days
Designated as hedging instrument | Net investment hedges
Derivative [Line Items]
US$ Notional	$ 87.6	$ 73.9
Years Average Maturity	6 months	9 months 18 days
Not designated as hedging instrument
Derivative [Line Items]
US$ Notional	$ 2,653.3	$ 2,968.6
Years Average Maturity	1 year 2 months 12 days	1 year 2 months 12 days