Ameren Corporation operates as a public utility holding company in the United States. It operates through four segments: Ameren Missouri, Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Transmission. The company is involved in the rate-regulated electric generation, transmission, and distribution activities; and rate-regulated natural gas transmission and distribution businesses. It primarily generates electricity through coal, nuclear, and natural gas, as well as renewable sources, such as hydroelectric, methane gas, and solar. The company serves residential, commercial, and industrial customers. It supplies electric service to 1.2 million customers and natural gas service to 0.1 million customer in central and eastern Missouri; and electric service to 1.2 million customers and natural gas service to 0.8 million customers in central and southern Illinois. The company was founded in 1881 and is headquartered in St. Louis, Missouri.