ONEOK, Inc. is an energy midstream service provider in the United States. The Company owns and operates natural gas liquids (NGL) systems, and is engaged in the gathering, processing, storage and transportation of natural gas. THe Company's operations include a 38,000-mile integrated network of NGL and natural gas pipelines, processing plants, fractionators and storage facilities in the Mid-Continent, Williston, Permian and Rocky Mountain regions. The Company operates through three business segments. The Natural Gas Gathering and Processing segment provides midstream services to contracted producers in North Dakota, Montana, Wyoming, Kansas and Oklahoma. The Natural Gas Liquids segment owns and operates facilities that gather, fractionate, treat and distribute NGLs and store NGL products primarily in the Mid-Continental, Permian Basin and the Rocky Mountain regions. The Natural Gas Pipelines segment provides transportation and storage services to end users.