There are many people who think that the Onccor electric to be also the light company of Dallas. Oncor was before a part of TXU energy. The main job of Oncor is to maintain the poles and wires and it also takes care of the maintenance, distraction and infrastructure that helps in keeping the lights on in Dallas. It also serves for Fort Worth and most of the parts of North Texas. At a point, the TXU energy was called the Light company of Dallas and the other North Texas area. TXU was also a unit of vertically aligned electricity. They also owned the sales generation and the retail sales of the Company. Deregulation in the electricity market happened in texas in the year of 1999. Because of this the TXu unit which was known as the light company was split with 3 walls. Now the TXU had three groups that were operating. One was the TXY retail energy, the other is the TXU distribution and the last one is called the TXU power generation. Dallas Electricity Plans are unique.

At the year of 2007, TXY was acquired in the biggest equity buy at that time. This TXU was then renamed as Energy future holdings.