All of that hard and easily liquidated currency is known as the M0 money supply. This includes the bills and coins in people's pockets and mattresses, the money on hand in bank vaults and all of the deposits those banks have at reserve banks [source: Hamilton]. According to the Federal Reserve, there was $908.6 billion in the M0 supply stream as of July 2009 [source: Federal Reserve]
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M1 represents all of the currency in the M0 money supply, plus all of the money held in checking accounts and other checkable accounts, as well as all of the money in travelers' checks. In July 2009, the M1 money supply for U.S. dollars equaled about $1,655.6 billion [source: Federal Reserve].
http://money.howstuffworks.com/how-m...-the-world.htm
So we are looking at about $700 billion in checking accounts as of two years ago.