Short-Term and Long-Term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Current portion of long-term debt	$ 308.0	$ 8.6
Reported Value Measurement
Debt Instrument [Line Items]
Current portion of long-term debt	308.0	8.6
Long-term debt	2,559.3	2,862.9
Estimate of Fair Value Measurement
Debt Instrument [Line Items]
Current portion of long-term debt	302.6	8.6
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Long-term debt	$ 2,223.6	$ 2,442.6