Enbridge Energy Partners, L.P. owns and operates crude oil and liquid petroleum transportation and storage assets; and natural gas gathering, treating, processing, transportation, and marketing assets in the United States. It operates through two segments, Liquids and Natural Gas. The Liquids segment operates Lakehead system that consists of interstate common carrier crude oil and liquid petroleum pipelines and storage assets, which serves Great Lakes and the Midwest regions of the United States, and the province of Ontario, Canada; and the North Dakota crude oil system. Its Mid-Continent system consists of approximately 1,666 miles of crude oil pipelines and approximately 21.4 million barrels of storage capacity, which serve refineries in the United States Mid-Continent region. This segment serves integrated oil companies, independent oil producers, and refiners and marketers. The Natural Gas segment owns and operates natural gas and natural gas liquids (NGL) gathering and transportation pipeline systems; natural gas processing and treating facilities; and NGL fractionation facilities, as well as provides trucking, rail, and liquids marketing services. This segment also offers supply, transmission, storage, and sales services to producers and wholesale customers, as well as other interconnected pipeline systems. It primarily serves wholesale customers, such as refiners and petrochemical producers, fractionators, and propane distributors, as well as industrial, utility, and power plant customers. Enbridge Energy Company, Inc. operates as a general partner of the company. The company was formerly known as Lakehead Pipe Line Partners, L.P. and changed its name to Enbridge Energy Partners, L.P. in 2001. Enbridge Energy Partners, L.P. was founded in 1991 and is headquartered in Houston, Texas.