Derivatives (Derivatives in Cash Flow Hedging Relationships) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Not Designated as Hedging Instrument [Member]
Effect of Derivative Instruments on Consolidated Statements of Operations
Amount of Loss (Gain) Recognized in Income on Derivatives	$ (7.6)	$ 3.4	$ 2.8
Not Designated as Hedging Instrument [Member] | Losses and Other Expenses, Net [Member] | Commodity Futures Contracts [Member]
Effect of Derivative Instruments on Consolidated Statements of Operations
Amount of Loss (Gain) Recognized in Income on Derivatives	(1.9)	(0.9)	2.5
Not Designated as Hedging Instrument [Member] | Losses and Other Expenses, Net [Member] | Foreign Currency Forward Contracts [Member]
Effect of Derivative Instruments on Consolidated Statements of Operations
Amount of Loss (Gain) Recognized in Income on Derivatives	(5.7)	4.3	0.3
Cash Flow Hedging [Member] | Cost of Goods Sold [Member] | Commodity Futures Contracts [Member]
Effect of Derivative Instruments on Consolidated Statements of Operations
Amount of Loss (Gain) Reclassified from AOCI into Income (Effective Portion)	(13.7)	12.3	12.5
Cash Flow Hedging [Member] | Losses and Other Expenses, Net [Member] | Commodity Futures Contracts [Member]
Effect of Derivative Instruments on Consolidated Statements of Operations
Amount of Loss (Gain) Recognized in Income on Derivatives (Ineffective Portion)	$ 1.0	$ (1.6)	$ 0.1