Exelon Corp. operates as a utility services holding company, which engages in the energy generation, power marketing, and energy delivery business. It operates through the following segments: Mid Atlantic, Midwest, New York, Electric Reliability Council of Texas (ERCOT) and other Power Regions. The Mid-Atlantic segment represents operations in the eastern half of PJM, which includes New Jersey, Maryland, Virginia, West Virginia, Delaware, the District of Columbia and parts of Pennsylvania and North Carolina. The Midwest segment operates in the western half of PJM, which includes portions of Illinois, Pennsylvania, Indiana, Ohio, Michigan, Kentucky and Tennessee, and the United States footprint of MISO, excluding MISO's Southern Region, which covers all or most of North Dakota, South Dakota, Nebraska, Minnesota, Iowa, Wisconsin, the remaining parts of Illinois, Indiana, Michigan and Ohio not covered by PJM, and parts of Montana, Missouri and Kentucky. The New York (NY) segment provides operations within ISONY, which covers the state of New York in its entirety. The ERCOT segment includes operations within Electric Reliability Council of Texas, covering most of the state of Texas.