Derivatives (Locations and Amounts of Derivative Fair Values) (Details) - Fair Value, Inputs, Level 2 [Member] - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total Assets	$ 11.7	$ 11.1
Total Liabilities	0.3	0.8
Designated as Hedging Instrument [Member] | Commodity Futures Contracts [Member] | Current Assets [Member]
Derivatives, Fair Value [Line Items]
Total Assets	11.0	8.7
Designated as Hedging Instrument [Member] | Commodity Futures Contracts [Member] | Non-Current Assets [Member]
Derivatives, Fair Value [Line Items]
Total Assets	0.6	1.9
Designated as Hedging Instrument [Member] | Commodity Futures Contracts [Member] | Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Liabilities	0.0	0.0
Designated as Hedging Instrument [Member] | Foreign Currency Forward Contracts [Member] | Current Assets [Member]
Derivatives, Fair Value [Line Items]
Total Assets	0.1	0.5
Designated as Hedging Instrument [Member] | Foreign Currency Forward Contracts [Member] | Non-Current Assets [Member]
Derivatives, Fair Value [Line Items]
Total Assets	0.0	0.0
Designated as Hedging Instrument [Member] | Foreign Currency Forward Contracts [Member] | Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Liabilities	0.3	0.8
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total Assets	2.2	1.1
Total Liabilities	1.1	3.2
Not Designated as Hedging Instrument [Member] | Commodity Futures Contracts [Member] | Current Assets [Member]
Derivatives, Fair Value [Line Items]
Total Assets	1.2	0.7
Not Designated as Hedging Instrument [Member] | Commodity Futures Contracts [Member] | Non-Current Assets [Member]
Derivatives, Fair Value [Line Items]
Total Assets	0.1	0.2
Not Designated as Hedging Instrument [Member] | Commodity Futures Contracts [Member] | Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Liabilities	0.0	0.0
Not Designated as Hedging Instrument [Member] | Foreign Currency Forward Contracts [Member] | Current Assets [Member]
Derivatives, Fair Value [Line Items]
Total Assets	0.9	0.2
Not Designated as Hedging Instrument [Member] | Foreign Currency Forward Contracts [Member] | Non-Current Assets [Member]
Derivatives, Fair Value [Line Items]
Total Assets	0.0	0.0
Not Designated as Hedging Instrument [Member] | Foreign Currency Forward Contracts [Member] | Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Liabilities	$ 1.1	$ 3.2