Alliant Energy Corporation is a holding company with subsidiaries engaged in regulated electric and natural gas services. The company operates primarily through four wholly owned subsidiaries: Interstate Power and Light Company (IPL), Wisconsin Power and Light Company (WPL), Resource and Corporate Services. Alliant Energy provides services to electric and natural gas customers in the Midwest. Its Utility Business segment includes the operations of IPL and WPL. Both the utilities have a diversified fuel mix which consists of coal, natural gas and renewable resources. The output from these generating facilities is supplemented with purchased power. IPL is primarily engaged in the generation and distribution of electricity and distribution and transportation of natural gas in select markets in Iowa and southern Minnesota.