Derivative Instruments, Derivatives Gains and Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
(Losses) Gains recognized due to cash flow ineffectiveness	$ 21.6	$ 6.3	$ (2.5)
Gain (Loss) from Components Excluded from Assessment of Cash Flow Hedge Effectiveness, Net	0.0	0.0	0.0
Accumulated Other Comprehensive Loss, Cumulative Changes in Net Loss from Cash Flow Hedges, Effect Net of Tax	39.7
Cash flow hedge gain to be reclassified within twelve months	23.5
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	0.0	0.0	0.0
Cost of goods sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0.5	14.7	0.4
OTC commodity swaps [Member] | Cost of goods sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	(10.2)	131.7	(2.9)
Derivatives designated as hedging instruments [Member] | OTC commodity swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0.7	22.6	0.7
(Losses) Gains recognized due to cash flow ineffectiveness	(21.5)	6.3	(2.5)
Derivatives not designated as hedging instruments [Member] | OTC commodity swaps [Member] | Cost of goods sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivatives not designated as hedging instruments	10.6	102.8	(1.1)
Derivatives not designated as hedging instruments [Member] | Interest Rate Contract [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Loss on Derivative	$ 0.2	$ 0.4	$ 0.4