...+ Duke Energy Corp. (Duke) is acquiring Piedmont Natural Gas Co. Inc. (Piedmont) in a transaction valued at $6.7 billion, including the assumption of $1.8 billion of debt. + We are affirming our ratings on Duke and all its subsidiaries, including the 'A-' issuer credit rating, and revising the outlook to negative from stable. + The negative outlook reflects our assessment that although Duke's business risk profile will benefit modestly through the addition of primarily regulated utility assets, its financial profile will weaken somewhat based on the terms of the proposed financing. NEW YORK (Standard & Poor's) Oct. 27, 2015--Standard & Poor's Ratings Services today affirmed its ratings on Duke Energy Corp. and subsidiaries, including the 'A-' issuer credit rating, and revised the outlook to negative from stable. The ratings affirmation on Duke and its subsidiaries reflects our view that the acquisition of Piedmont will modestly enhance Duke's business risk profile, given that the vast majority...