ONEOK's ("one oak") one business focus is energy. Through its 41%-owned ONEOK Partners (of which it is the general partner) it operates 11,300 miles of gas-gathering pipeline and 7,600 miles of transportation pipeline, as well as gas processing plants and storage facilities. The unit also owns one of the US's top natural gas liquids (NGL) systems. ONEOK's energy services unit focuses on marketing natural gas across the US. To focus on its core pipeline businesses, in 2014 ONEOK spun off its regulated utilities (Oklahoma Natural Gas, Kansas Gas Service, and Texas Gas Service, which distribute natural gas to more than 2.1 million customers) as ONE Gas.