We all know about TARP, the Troubled Asset Relief Program, which spent $700 billion in taxpayers' money to bail out banks after the financial crisis. That money was scrutinized by Congress and the media.

But it turns out that that $700 billion is just a small part of a much larger pool of money that has gone into propping up our nation's financial system. And most of that taxpayer money hasn't had much public scrutiny at all.