Plains All American Pipeline LP through its subsidiaries, engages in the pipeline transportation, terminaling, storage, and gathering of crude oil and natural gas liquids (NGL) in the United States and Canada. The company operates through two segments, Crude Oil and NGL. The Crude Oil segment offers gathering and transporting crude oil through pipelines, gathering systems, trucks, and barges or railcars. The NGL segment is involved in natural gas processing and NGL fractionation, storage, transportation, and terminalling. It generates the majority of its revenue from the Crude Oil segment.