CenterPoint Energy, Inc. operates as a public utility holding company. It engages in the transmission and distribution of electricity to retail electric providers (REPs), municipalities, electric cooperatives, and other distribution companies serving approximately 2 million metered customers in Texas. As of December 31, 2011, it owned 27,952 pole miles of overhead distribution lines and 3,716 circuit miles of overhead transmission lines; 20,781 circuit miles of underground distribution lines and 26 circuit miles of underground transmission lines; and 232 substations with a capacity of 52,732 megavolt amperes. The company is also involved in regulated intrastate natural gas sales to, and natural gas transportation for approximately 3.3 million residential, commercial, and industrial customers; provides various unregulated services consisting of heating, ventilating, and air conditioning (HVAC) equipment and appliance repair; and sells HVAC, and hearth and water heating equipment. As of December 31, 2011, it owned approximately 72,000 linear miles of natural gas distribution mains. In addition, the company offers physical natural gas supplies to commercial and industrial customers, and electric and gas utilities; natural gas management services; physical delivery services and financial products; and storage and transportation services. It owns and operates approximately 8,000 miles of natural gas transmission lines primarily in Arkansas, Illinois, Louisiana, Missouri, Oklahoma, and Texas; and 6 natural gas storage fields. Further, CenterPoint Energy, Inc. provides operating and technical services, and remote data monitoring and communication services; and owns and operates approximately 3,900 miles of gathering lines and processing plants that collect, treat, and process natural gas. The company was founded in 1882 and is headquartered in Houston, Texas.