FirstEnergy Corp. is a holding company. The Company is a diversified energy company operating in three segments: regulated distribution, regulated transmission and competitive energy services segment. Regulated Distribution segment distributes electricity through its 10 utility operating companies, serving within 65,000 square miles of Ohio, Pennsylvania, West Virginia, Maryland, New Jersey and New York. Regulated Transmission segment transmits electricity through transmission facilities owned and operated by American Transmission Systems, Incorporated (ATSI) and Trans-Allegheny Interstate Line Company (TrAIL). Competitive Energy Services segment, through FirstEnergy Solutions Corp. ( FES) and Allegheny Energy Supply Company, LLC (AE Supply), supplies electricity to end-use customers through retail and wholesale arrangements, and the provision of partial provider of last resort (POLR) and default service for some utilities in Ohio, Pennsylvania and Maryland, including the Utilities.