Integrys Energy Group, Inc. operates as an energy holding company with natural gas and electric utility operations in the United States. It operates through Natural Gas Utility, Electric Utility, and Electric Transmission Investment segments. The company offers natural gas services to approximately 1.7 million residential, commercial and industrial, transportation, and other customers in Chicago and the northern suburbs of Chicago, northeastern Wisconsin, various cities and communities in Minnesota, and the southern portion of lower Michigan, as well as in Michigan s Upper Peninsula. It also provides electric services to approximately 450,000 residential, commercial and industrial, wholesale, and other customers in northeastern Wisconsin and Michigan s Upper Peninsula; and wholesale electric services to various customers, including municipal utilities, electric cooperatives, energy marketers, other investor-owned utilities, and municipal joint action agencies. In addition, the company owns and operates the electric transmission system in parts of Wisconsin, Illinois, Minnesota, and the Upper Peninsula of Michigan; and designs, builds, maintains, owns, and/or operates compressed natural gas fueling stations in various states. Further, it invests in distributed renewable energy projects, as well as owns natural gas-fired cogeneration facility in Wisconsin. Integrys Energy Group, Inc. was founded in 1883 and is headquartered in Chicago, Illinois.