The Houston couple with three children work full time to give away John's $2.8 billion fortune. He made his money as a top trader at Enron and through the Centaurus Energy hedge fund he started in 2002 and closed a decade later. Laura Arnold was executive vice president and general counsel of Cobalt International Energy and was a mergers and acquisitions attorney at Wachtell, Lipton, Rosen and Katz in New York City. He is a native of Dallas; she is a native of Puerto Rico.