v2.4.0.6
Financial Instruments (Details 1) (Fuel Hedges [Member], USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Fuel Hedges [Member]
   
Impact of hedges on results of operations and comprehensive income    
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion) $ 1.3 $ 7.7