Derivative Instruments (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Effect of mark to market valuation [Member]
Other Derivatives
Other Derivatives	$ (0.1)	$ (0.3)	$ 0	$ 0.2
Settlements [Member]
Other Derivatives
Other Derivatives	(0.1)	0.1	0	0.1
Commodity Contract [Member]
Other Derivatives
Other Derivatives	(0.2)	(0.2)	0	0.3
Foreign exchange hedges [Member]
Other Derivatives
Other Derivatives	$ 0		$ (0.4)	$ (0.6)