Over a five-hour conversation, Deputy Crown Prince Mohammed bin Salman laid out his vision for the Public Investment Fund, which will eventually control more than $2 trillion and help wean the kingdom off oil. As part of that strategy, the prince said Saudi will sell shares in Aramco's parent company and transform the oil giant into an industrial conglomerate. The initial public offering could happen as soon as next year, with the country currently planning to sell less than 5 percent.

"IPOing Aramco and transferring its shares to PIF will technically make investments the source of Saudi government revenue, not oil," the prince said in an interview at the royal compound in Riyadh that ended at 4 a.m. on Thursday. "What is left now is to diversify investments. So within 20 years, we will be an economy or state that doesn't depend mainly on oil."