NEW YORK--(BUSINESS WIRE)--Fitch Ratings has affirmed the 'BBB-' long-term Issuer Default Ratings (IDRs) of NiSource Inc. (NI) and its subsidiaries. Fitch has also revised NI's Rating Outlook to Positive from Stable in anticipation of its separation from Columbia Pipeline Group (CPG, IDR 'BBB-'/Outlook Stable) on July 1, 2015. After the separation, NI will become a fully regulated natural gas and electric utility holding company. A complete list of rating actions is provided at the end of this