Derivatives, Hedging Programs and Other Financial Instruments, Balance Sheet (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Derivative Asset	$ 11.4	$ 25.3
Derivative Liability	5.5	0.8
Other Current Assets [Member]
Derivative [Line Items]
Derivative Asset	9.0	18.9
Other Assets [Member]
Derivative [Line Items]
Derivative Asset	2.4	6.4
Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability	3.1	0.3
Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative Liability	$ 2.4	$ 0.5