Debt and Credit Facilities (Short-Term Borrowings and Current Maturities of Long-Term Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Short-term borrowings and current maturities of long-term debt	$ 361.0	$ 504.2
Debentures With Put Feature [Member]
Short-term borrowings and current maturities of long-term debt	343.0	343.0
Current Maturities Of Long Term Debt [Member]
Short-term borrowings and current maturities of long-term debt	7.7	7.8
Other Short Term Borrowings [Member]
Short-term borrowings and current maturities of long-term debt	10.3	10.4
Commercial Paper [Member]
Short-term borrowings and current maturities of long-term debt	$ 0.0	$ 143.0