Summary of Significant Accounting Policies Accumulated Other Comprehensive Loss - Reclassifications Out of Accumulated OCI (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Gains (Losses) on Cash Flow Hedges, Amount Reclassified from Accumulated OCI	$ (0.5)
Gains (Losses) on Cash Flow Hedges, Amount Reclassified from Accumulated OCI, Tax	(0.2)
Gains (Losses) on Cash Flow Hedges, Amount Reclassified from Accumulated OCI, Net of Tax	(0.3)
Commodity Contract [Member]
Gains (Losses) on Cash Flow Hedges, Amount Reclassified from Accumulated OCI	$ (0.5)