Sources on Capitol Hill told Reid that the stimulus package could grow to at least $850 billion, which is about double the cost, in today's dollars, of the interstate highway system and more than the United States has spent on the Iraq war.
With consumers not spending, and more and more businesses laying off workers, some economists say there's no alternative.
"Government is the difference between a bad recession and very bad depression," Mark Zandi of Moody's told CBS News.
But deficit hawks on the Hill and some conservative economists argue that continuing to throw money at the economic meltdown will only make it worse.
"It didn't work the first time, it's not going to work this time," said J.D. Foster of the Heritage Foundation. "The only thing that it has in common is that it's going to leave us with a hangover."
Democratic leaders are hoping to move the stimulus package through Congress at rapid speed. They want to have it ready for Mr. Obama's signature about ten days after he's sworn in as president.