Basis of Accounting Presentation Basis of Accounting Presentation (Details)
9 Months Ended
Sep. 30, 2015
mi
Basis Of Accounting Presentation [Line Items]  
Pipeline Miles 15,000
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest 15.70%
Corporate Joint Venture [Member]  
Basis Of Accounting Presentation [Line Items]  
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest 84.30%