Other, Net (Schedule of Other, Net) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Schedule Of Other, Net [Line Items]    
AFUDC Equity $ 3.5  
Miscellaneous 0.8  
Total Other, net 4.3  
Predecessor [Member]    
Schedule Of Other, Net [Line Items]    
AFUDC Equity   1.6
Miscellaneous   0.2
Total Other, net   $ 1.8