It was July 1974. William Simon, newly appointed U.S. Treasury secretary, and his deputy, Gerry Parsky, stepped onto an 8 a.m. flight. [Simon's] mission, kept in strict confidence within President Richard Nixon's inner circle, would take place during a four-day layover in the coastal city of Jeddah, Saudi Arabia. The goal: persuade a hostile kingdom to finance America's widening deficit with its newfound petrodollar wealth. The United States would buy oil from Saudi Arabia and provide the kingdom military aid and equipment. In return, the Saudis would plow billions of their petrodollar revenue back into Treasuries and finance America's spending. At the end of months of negotiations, there remained one small, yet crucial, catch: King Faisal bin Abdulaziz Al Saud demanded the country's Treasury purchases stay strictly secret." With a handful of Treasury and Federal Reserve officials, the secret was kept for more than four decades. In response to a Freedom-of-Information-Act request submitted by Bloomberg News, the Treasury broke out Saudi Arabia's holdings for the first time this month. The $117 billion trove makes the kingdom one of America's largest foreign creditors. A former Treasury official ... says the official figure vastly understates Saudi Arabia's investments in U.S. government debt, which may be double or more. In April, Saudi Arabia warned it would start selling as much as $750 billion in Treasuries and other assets if Congress passes a bill allowing the kingdom to be held liable in U.S. courts for the Sept. 11 terrorist attacks.