Short-Term and Long-Term Debt - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2024	Apr. 25, 2024	Sep. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Short-term debt	$ 816.5		$ 94.7
Commercial Paper
Debt Instrument [Line Items]
Short-term debt	$ 704.0
Debt, weighted average interest rate	5.38%
Debt instrument, term	22 days
Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity				$ 75.0
Short-term bank loans and notes payable	$ 70.0		$ 70.0
Stated interest rate	6.17%		6.29%
Interest Bearing Loan
Debt Instrument [Line Items]
Short-term debt		$ 18.8	$ 23.5
Long-term debt	$ 23.5