NorthWestern Corporation, doing business as NorthWestern Energy, provides electricity and natural gas. The Company's segments include electric utility operations, natural gas utility operations, and all other. Its electric utility operations segment primarily provides generation, transmission, and distribution of electricity services to its customers in Montana and South Dakota jurisdictions. The natural gas utility operations segment provides production, storage, transmission, and distribution of natural gas services to its customers in Montana, South Dakota and Nebraska jurisdictions. Its electric utility business in Montana includes generation, transmission and distribution and provides electricity to approximately 398,200 customers in 221 communities. Its South Dakota electric utility business provide retail electricity to more than 64,700 customers in 116 communities in South Dakota. The Company distributes natural gas to approximately 209,100 customers in 118 Montana communities.