Derivative Instruments And Hedging Activities (Effect Of Derivative Financial Instruments On The Statements Of Income And Comprehensive Income) (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011		Sep. 30, 2010
Interest Rate Cap [Member] | Not-Designated [Member] | Other Income Expense [Member]
Amount of Loss Recognized in Income on Derivative	$ (0.1)		$ (0.1)
Interest Rate Swaps [Member] | Cash Flow Hedge [Member]
Amount of (Loss) Recognized in Other Comprehensive Income ("OCI") on Derivative (Effective Portion)		(5.3)	(2.7)	[1]	(19.5)	[1]
Interest Rate Swaps [Member] | Not-Designated [Member] | Other Income Expense [Member]
Amount of Loss Recognized in Income on Derivative	(0.1)		(0.1)
Cash Flow Hedge [Member] | Loss On Discontinuation Of Hedging Relationship [Member]
Amount of Loss Recognized in Income on Derivative (Discontinuation, Ineffective Portion and Amount Excluded from Effectiveness Testing)			(29.8)	[1]		[1]
Cash Flow Hedge [Member] | Interest Expense [Member]
Amount of Loss Reclassified from Accumulated OCI into Income (Effective Portion)	$ 0.1	$ 5.8	$ 9.9	[1]	$ 17.5	[1]

[1] The results include the interest rate swap gain (loss) prior to discontinuation in May 2011.