TransCanada PipeLines Limited operates as an energy infrastructure company in North America. The company operates in three segments: Natural Gas Pipelines, Oil Pipelines, and Energy. The Natural Gas Pipelines segment operates natural gas pipelines, regulated gas storage facilities, and projects related to oil pipelines in Canada, the United States, and Mexico. Its natural gas pipeline systems consist of a network of approximately 60,000 kilometers (km) of wholly owned and operated natural gas pipelines and approximately 8,800 km of partially owned natural gas pipelines; and regulated natural gas storage facilities with a total capacity of approximately 250 billion cubic feet (Bcf) in Michigan. The Oil Pipelines segment operates crude oil pipeline system that carries 1.1 million barrels per day. Its crude oil pipeline system comprises completed 3,467 km Wood River/Patoka and Cushing Extension phases; and a proposed 2,673 km the United States Gulf Coast Expansion project. The Energy segment engages in the acquisition, development, construction, ownership, and operation of electrical power generation plants; purchase and marketing of electricity; provision of electricity account services to energy and industrial customers; and development, construction, ownership, and operation of non-regulated natural gas storage in Alberta. This segment owns, controls, and develops approximately 10,800 mega watt of power generation, including power sourced from natural gas, nuclear, coal, hydro, and wind assets; and owns or controls approximately 130 Bcf of non-regulated natural gas storage capacity. The company was formerly known as Trans-Canada Pipe Lines Limited and changed its name to TransCanada PipeLines Limited in April 1972. TransCanada PipeLines Limited was incorporated in 1951 and is headquartered in Calgary, Canada. TransCanada PipeLines Limited is a subsidiary of TransCanada Corporation.