Scott Duncan is the youngest of the four Duncan heirs, the children of Dan Duncan (d. 2010), founder of an energy-pipeline empire. Enterprise Products Partners today owns nearly 51,000 miles of natural gas, oil and petrochemical pipelines. His sister Randa Duncan Williams is the non-executive Chairman of the board. His two other siblings, Dannine Avara and Milane Frantz, are also billionaires. Unlike Dannine, Milane and Scott, Randa has taken a role running the business.