The money is being cut, counted and bundled for delivery to every branch bank in America, plus in several secret storage sites in the event more is needed.
CBS News Correspondent Jim Stewart explains what else is in store in his "Eye On America" report.
Alarmed by doomsday books urging everyone to sock away thousands in cash, the Federal Reserve and banks are planning for the worst. Every armored car in America was booked months ago for Y2K weekend cash deliveries. Banks have canceled vacations, extra guards have been added, and already there are signs of some panic withdrawals.
"I had one financial institution tell me that a little old lady came in and withdrew $90,000 - closing her account out - and she was going to keep it at home with her," said Dan Connelly, president of Armored Courier Service.
Texas Banking Commissioner Catherine Ghiglieri mentioned another case: "I was told that a group of companies was going to pull one month's cash out of the banks. And I said, 'Where are you going to put that?' and 'Why are you going to do that?'"
The problem isn't computers. Banks worked out the bugs in those a long time ago. Bankers say the real problem now is people. Despite every reassurance, some people still believe that come the millennium, everything, including their bank accounts, will be shut down.
And what bankers really fear is that, for some reason, an ATM machine somewhere might not work on Saturday New Year's Day and start a panic run on the banks reminiscent of the Great Depression. Hence the extra cash.
Alexander Boyle, vice chairman of Chevy Chase Bank in Maryland, said that if the unthinkable did happen and suddenly there is a line of people snaking out the front door, he has a plan. "We have an armored car service prepared to deliver additional amounts of cash to each branch if necessary."
But there are other potential problems. The FBI and banks are already briefing senior citizens on the danger of being robbed at year's end.
And that's not to mention the pain in the neck it will be next January to count and return that $50 billion to the Federal Reserve, all 18 million pounds of it.
For more Y2K information, go to the FDIC Web site.
And for other Y2K government links, click here.