Financial Instruments and Risk Management (Narrative) (Details) $ in Millions	3 Months Ended
	Dec. 31, 2025 USD ($) contracts	Dec. 31, 2024 USD ($)	Sep. 30, 2025 USD ($)
Derivative [Line Items]
Total	$ 1,527.0		$ 1,390.0
FX contract | Not designated as hedge
Derivative [Line Items]
Estimated fair value of derivatives	$ 0.0		0.1
Open foreign currency contracts | contracts	1
Derivative, notional amount	$ 9.0
Gain (loss) recognized in income	0.6	$ 0.9
FX contract | Cash flow hedge | Designated as hedge
Derivative [Line Items]
Estimated fair value of derivatives	$ 0.8		(1.4)
Open foreign currency contracts | contracts	64
Derivative, notional amount	$ 122.1
Revolving credit facility
Derivative [Line Items]
Total	277.0		140.0
Fixed rate
Derivative [Line Items]
Total	1,250.0		1,250.0
Fair value of long-term debt	$ 1,196.8		$ 1,198.2