Lines of Credit and Financing Arrangements (Outstanding Debt Obligations) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Commercial paper	$ 0.0	$ 150.0
Current maturities of long-term debt:
Finance lease obligations	14.9	12.1
Senior unsecured notes	314.5	12.1
Long-Term Debt:
Finance lease obligations	39.5	32.7
Total long-term debt	833.1	1,143.1
Debt Issuance Cost, Gross, Noncurrent	(6.4)	(9.6)
Total debt	1,147.6	1,305.2
Domestic Credit Facility [Member]
Current maturities of long-term debt:
Debt issuance costs	(0.4)	0.0
Senior unsecured notes	300.0	0.0
Long-Term Debt:
Total long-term debt	0.0	20.0
Senior Unsecured Notes [Member]
Long-Term Debt:
Total long-term debt	$ 800.0	$ 1,100.0