Xcel Energy Inc. is a public utility holding company. The Company's operations include activity of four utility subsidiaries that serve electric and natural gas customers. Its segments are regulated electric utility, regulated natural gas utility and all other. The regulated electric utility segment generates, transmits and distributes electricity in Minnesota, Wisconsin, Michigan, North Dakota, South Dakota, Colorado, Texas and New Mexico. The regulated electric utility segment also includes commodity trading operations. The regulated natural gas utility segment transports, stores and distributes natural gas primarily in portions of Minnesota, Wisconsin, North Dakota, Michigan and Colorado. The all other category primarily includes steam revenue, appliance repair services, nonutility real estate activities, revenues associated with processing solid waste into refuse-derived fuel and investments in rental housing projects that qualify for low-income housing tax credits.