Debt (Repayments) (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Oct. 31, 2025
Debt Instrument [Line Items]
Payments on long-term debt	$ 588.7	$ 332.3
Senior Note One Point Five Percent | Senior Notes
Debt Instrument [Line Items]
Payments on long-term debt	$ 550.0
Interest rate			1.50%