Lines of Credit and Financing Arrangements (Outstanding Debt Obligations) (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Commercial paper	$ 29.0	$ 0.0
Current maturities of long-term debt:
Finance lease obligations	16.5	14.9
Debt issuance costs	(0.1)	(0.4)
Total current maturities of long-term debt	316.4	314.5
Long-Term Debt:
Finance lease obligations	42.7	39.5
Debt issuance costs	(7.0)	(6.4)
Total long-term debt	835.7	833.1
Total debt	1,181.1	1,147.6
Senior Unsecured Notes
Current maturities of long-term debt:
Senior unsecured notes	300.0	300.0
Long-Term Debt:
Domestic credit facility and senior unsecured notes	$ 800.0	$ 800.0