Financial Instruments (Interest Rate Management Contracts and Cross Currency Interest Rate Swaps) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Interest rate swaps contracts | Designated as Hedging Instrument | Fair value hedges
Derivative [Line Items]
Notional Principal amount	$ 800.0	$ 800.0
Average Pay %	SOFR	Various
Average Receive %	1.64%	1.64%
Years Average Maturity	4 years	5 years
Interest rate swaps contracts | Designated as Hedging Instrument | Cash flow hedges
Derivative [Line Items]
Notional Principal amount	$ 1,182.5	$ 0.0
Average Pay %	2.82%	0.00%
Years Average Maturity	22 years 1 month 6 days	0 years
Derivative Description of Variable Rate Basis-Receive	SOFR	—
Cross currency interest rate swaps | Designated as Hedging Instrument | Net investment hedges
Derivative [Line Items]
Notional Principal amount	$ 80.8	$ 176.7
Average Pay %	4.60%	4.12%
Average Receive %	3.65%	3.07%
Years Average Maturity	10 months 24 days	1 year 2 months 12 days
Cross currency interest rate swaps | Designated as Hedging Instrument | Cash flow hedges
Derivative [Line Items]
Notional Principal amount	$ 598.2	$ 785.7
Average Pay %	4.89%	4.78%
Average Receive %	3.22%	3.05%
Years Average Maturity	2 years 2 months 12 days	2 years 3 months 18 days
Cross currency interest rate swaps | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional Principal amount	$ 44.5	$ 37.7
Average Pay %	5.39%	5.39%
Average Receive %	3.54%	3.54%
Years Average Maturity	2 months 12 days	1 year 2 months 12 days