Debt and Credit Facilities (Short-Term Borrowings and Current Maturities of Long-Term Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Short-term borrowings and current maturities of long-term debt	$ 350.4	$ 350.4
Debentures With Put Feature [Member]
Short-term borrowings and current maturities of long-term debt	342.9	342.9
Commercial Paper [Member]
Short-term borrowings and current maturities of long-term debt	0.0	0.0
Current Maturities Of Long Term Debt [Member]
Short-term borrowings and current maturities of long-term debt	$ 7.5	$ 7.5