MINNEAPOLIS (AP) _ Northern States Power Co. and Denver-based New Century Energies will be known as Xcel Energy Inc. when they merge, the utilities announced Tuesday.

The two companies announced in late March their plans to merge, with the transition expected to be complete within 12 to 18 months.

NSP provides electricity to about 1.5 million customers in parts of Minnesota, Wisconsin, North Dakota, Michigan and South Dakota. It also distributes natural gas to more than 475,000 customers in Minnesota, Wisconsin, North Dakota, Michigan and Arizona.

NCE serves about 1.6 million electricity customers and more than a million natural gas customers in Colorado, Texas, New Mexico, Wyoming, Kansas and Oklahoma.