Derivative Instruments and Hedging Activities (Summary Of Accumulated Other Comprehensive Loss Related To Derivatives) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Before-Tax Amount
Accumulated derivative net losses, Beginning Balance	$ (5.4)
Net changes in fair value of derivatives	(3.4)
Net loss reclassified from accumulated other comprehensive loss into income	5.6
Accumulated derivative net losses, Ending Balance	(3.2)
Income Tax
Accumulated derivative net losses, Beginning Balance	(1.1)
Net changes in fair value of derivatives	0.6
Net loss reclassified from accumulated other comprehensive loss into income	0.2
Accumulated derivative net losses, Ending Balance	(0.3)
After-Tax Amount
Accumulated derivative net losses, Beginning Balance	(4.3)
Net changes in fair value of derivatives	(4.0)
Net loss reclassified from accumulated other comprehensive loss into income	5.4
Accumulated derivative net losses, Ending Balance	$ (2.9)