Derivatives (Summary of Derivative Income Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (loss) on Derivative, Net			$ 1.9	$ 0
Gain (loss) on derivative activity	(1.0)	0	1.9	0
Commodity Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (loss) on Derivative, Net	(1.8)		0.2
Change in fair value of derivatives	0.8		1.7
Gain (loss) on derivative activity	$ (1.0)		$ 1.9