v2.4.0.6
Derivative Instruments and Hedging Activities (Details) (Interest Rate Swap, USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2011
Derivative  
Derivatives, Expected net loss to be transferred from accumulated OCI to earnings within 12 months $ 11.6
Swaps Effective February 2010
 
Derivative  
Notional Amount of Interest Rate Derivatives 1,000.0
Derivative, Weighted Average Fixed Interest Rate 5.927%
Derivative, Maturity Date Feb. 01, 2012
Swaps Effective February 2012
 
Derivative  
Notional Amount of Interest Rate Derivatives 950.0
Derivative, Weighted Average Fixed Interest Rate 4.908%
Derivative, Maturity Date Feb. 01, 2014
Swaps Effective April 2011
 
Derivative  
Notional Amount of Interest Rate Derivatives 450.0
Derivative, Weighted Average Fixed Interest Rate 5.242%
Derivative, Maturity Date Apr. 15, 2014
Designated as Hedging Instrument
 
Derivative  
Derivative, Net Liability Position, Aggregate Fair Value $ 21.0