The Group's principal activity consists of its regulated electricity transmission and distribution operations. The Group operates through three business segments: Electric Delivery, Natural Gas Delivery and Other segment. Electric Delivery segment consists of its regulated electricity transmission, distribution and generation operations in New York and Maine. Natural Gas Delivery segment includes regulated natural gas transportation, storage and distribution operations in New York, Connecticut, Maine and Massachusetts. Other segment includes the regulated liquefied natural gas peaking plant, retail energy marketing, natural gas delivery and propane air delivery. The Group also generates electricity from its share of a nuclear plant and its several hydroelectric stations. It serves approximately two million electricity customers and one million natural gas customers.