Income Taxes (Uncertain Tax Positions) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Income Tax Contingency [Line Items]      
Accrued liability for uncertain tax $ 28.9 $ 18.8 $ 0.6
Reconciliation of Unrecognized Tax Benefits, Excluding Interests and Penalties [Roll Forward]      
Additions for tax positions related to prior years 26.5    
Reductions for tax positions related to prior years (16.8)    
Additions based on tax positions related to the current year 0.4    
Balance at December 31   18.8  
Accrued interest for uncertain tax positions $ 4.7 $ 0.5