Debt and Credit Facilities (Short-Term Borrowings and Current Maturities of Long-Term Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Short-term borrowings and current maturities of long-term debt	$ 949.7	$ 650.3
Debentures With Put Feature [Member]
Short-term borrowings and current maturities of long-term debt	343.0	343.0
Two Point Six Two Five Percent Senior Notes Due Two Thousand Twenty [Member]
Short-term borrowings and current maturities of long-term debt	299.9	299.8
Commercial Paper [Member]
Short-term borrowings and current maturities of long-term debt		0.0
Current Maturities Of Long Term Debt [Member]
Short-term borrowings and current maturities of long-term debt	7.5	7.5
Two Point Nine Percent Senior Notes Due Two Thousand Twenty One [Member] [Member]
Short-term borrowings and current maturities of long-term debt	$ 299.3	$ 0.0