Short-Term and Long-Term Debt - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023
Debt Instrument [Line Items]
Short-term debt	$ 501.4	$ 94.7
Commercial Paper
Debt Instrument [Line Items]
Short-term debt	$ 407.0
Debt, weighted average interest rate	5.41%
Debt instrument, term	13 days
Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 75.0
Unsecured line of credit, amount borrowed	$ 70.0
Stated interest rate	6.25%	6.29%
Interest Bearing Loan
Debt Instrument [Line Items]
Short-term debt	$ 23.5	$ 23.5