El Paso Pipeline Partners, L.P. owns and operates interstate natural gas transportation and terminaling facilities. As of December 31, 2011, the Company owned Wyoming Interstate Company, L.L.C. (WIC), Southern LNG Company, L.L.C. (SLNG), Elba Express Company, L.L.C. (Elba Express), Southern Natural Gas Company, L.L.C. (SNG) and an 86% interest in Colorado Interstate Gas Company, L.L.C. (CIG). In March 2011, the Company acquired an additional 25% interest in SNG from El Paso Corporation (El Paso). In June 2011, it acquired the remaining 15% interest in SNG and an additional 28% interest in CIG from El Paso. During the year ended December 31, 2011, it acquired the remaining 40% general partner interest in SNG. Effective March 1, 2013, El Paso Pipeline Partners LP (El Paso Pipeline), a unit of El Paso Corp, acquired the remaining 14% stake in Colorado Interstate Gas Company, L.L.C.