CenterPoint Energy, Inc. operates as a public utility holding company in the United States. The company's Electric Transmission & Distribution segment engages in the transmission and distribution of electricity to retail electric providers (REPs), municipalities, electric cooperatives, and other distribution companies. As of December 31, 2012, this segment owned 28,011 pole miles of overhead distribution lines and 3,713 circuit miles of overhead transmission lines; 21,151 circuit miles of underground distribution lines and 26 circuit miles of underground transmission lines; and 233 substations with a capacity of 54,325 megavolt amperes. Its Natural Gas Distribution segment is involved in regulated intrastate natural gas sales to, and natural gas transportation for residential, commercial, and industrial customers; provides 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, 2012, this segment owned approximately 72,000 linear miles of natural gas distribution mains. The CenterPoint Energy, Inc.'s Competitive Natural Gas Sales and Services segment offers physical natural gas supplies primarily to commercial and industrial customers, and electric and gas utilities; natural gas management services; and physical delivery services and financial products. The company's Interstate Pipelines segment operates approximately 8,000 miles of natural gas transmission lines, and 6 natural gas storage fields. Its Field Services segment provides operating and technical services, and remote data monitoring and communication services; and owns and operates approximately 4,600 miles of gathering pipelines and processing plants that collect, treat, and process natural gas. The company was founded in 1882 and is headquartered in Houston, Texas.