NorthWestern Corporation doing business as NorthWestern Energy, provides electricity and natural gas to approximately 668,300 customers in Montana, South Dakota and Nebraska. The Company generates and distributes electricity in South Dakota and distributes natural gas in South Dakota and Nebraska. It generates and distributes electricity and distributed natural gas in Montana. The Company operates its business in three segments: electric operations; natural gas operations, and all other, which consists of a remaining unregulated natural gas contract, the wind down of its captive insurance subsidiary and its unallocated corporate costs. In December 2013, completed the purchase of operating and nonoperating natural gas production interests in northern Montana's Bear Paw Basin from Devon Energy Production Company, L.P.