Avista Corporation, together with its subsidiaries, operates as an electric and natural gas utility company in the United States. It operates through two segments, Avista Utilities and Alaska Electric Light and Power Company (AEL&P). The Avista Utilities segment provides electric distribution and transmission, and natural gas distribution and transmission services in parts of eastern Washington and northern Idaho; and natural gas distribution services in parts of northeastern and southwestern Oregon, as well as generates electricity in Washington, Idaho, Oregon, and Montana. This segment also engages in the supply of electricity to customers in Montana; and wholesale purchase and sale of electricity and natural gas.