Derivative Instruments and Hedging Activities (Summary Of Accumulated Other Comprehensive Loss Related To Derivatives) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Before-Tax Amount
Accumulated derivative net gains, Beginning Balance	$ 1.1
Net changes in fair value of derivatives	1.0
Net gains reclassified from accumulated other comprehensive loss into income	(0.6)
Accumulated derivative net gains, Ending Balance	1.5
Income Tax
Accumulated derivative net gains, Beginning Balance	0.4
Net changes in fair value of derivatives	0.3
Net gains reclassified from accumulated other comprehensive loss into income	(0.1)
Accumulated derivative net gains, Ending Balance	0.6
After-Tax Amount
Accumulated derivative net gains, Beginning Balance	0.7
Net changes in fair value of derivatives	0.7
Net gains reclassified from accumulated other comprehensive loss into income	(0.5)
Accumulated derivative net gains, Ending Balance	$ 0.9