NorthWestern Energy Group, Inc., doing business as NorthWestern Energy, provides essential energy infrastructure and valuable services. The Company operates through two segments: electric utility operations and natural gas utility operations. The electric utility operations segment includes the generation, purchase, transmission and distribution of electricity. The natural gas utility operations segment includes the production, purchase, transmission, storage, and distribution of natural gas. It provides electricity and / or natural gas to approximately 775,300 customers in Montana, South Dakota, Nebraska, and Yellowstone National Park. Its operations in Montana and Yellowstone National Park are conducted through its subsidiary, NorthWestern Corporation, and its operations in South Dakota and Nebraska are conducted through its subsidiary, NorthWestern Energy Public Service Corporation. Its customer base consists of a mix of residential, commercial, and diversified industrial customers.