Concentration Of Credit Risk (Tables)
3 Months Ended
Mar. 31, 2016
Risks and Uncertainties [Abstract]  
Schedule of Concentration Of Credit Risk
Three Months Ended March 31,
2016
 
2015
(in millions)
Total Operating Revenues
 
Percentage of Total Operating Revenues
 
Total Operating Revenues
 
Percentage of Total Operating Revenues
Columbia Gas of Ohio(1)
$
50.4

 
13.9
%
 
$
48.9

 
14.4
%
(1) Represents the gross amount of revenue contracted for with Columbia Gas of Ohio and, therefore, subject to risk at the loss of this customer. Columbia Gas of Ohio has entered into certain capacity release arrangements with third parties which ultimately can decrease the net revenue amount the Partnership receives from Columbia Gas of Ohio in any given period.