Other, Net (Schedule of Other, Net) (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2015
Sep. 30, 2014
Sep. 30, 2015
Sep. 30, 2014
Schedule Of Other, Net [Line Items]        
AFUDC Equity $ 6.6   $ 15.0  
Miscellaneous 2.8   3.6  
Total Other, net $ 9.4   $ 18.6  
Predecessor        
Schedule Of Other, Net [Line Items]        
AFUDC Equity   $ 3.9   $ 8.2
Miscellaneous   (0.3)   (0.2)
Total Other, net   $ 3.6   $ 8.0