Alliant Energy Corp. engages in the provision of regulated electricity and natural gas service to natural gas customers in the Midwest through its two public utility subsidiaries. It operates through the Utility and ATC Holdings, Non-Utility, Parent, and Other segments. The Utility segment includes the operations of IPL and WPL, which primarily serve retail customers in Iowa and Wisconsin. The ATC Holdings, Non-Utility, Parent, and Other segment refers to the operations of AEF and its subsidiaries, Corporate Services, the Alliant Energy parent company, and any Alliant Energy parent company consolidating adjustments. The company was founded in 1981 and is headquartered in Madison, WI.