The US Dollar is not a money, as it is not backed up by government or assets. It is a virtual credit note, created out of nothing (just a number added onto a balance sheet), and backed up by nothing but a “promise” to pay it back. The Federal Reserve can create endless US Dollars out of nothing, without having anything on their own to back it up aside from the ability to create just more of the same nothing. The Fed “gives” this nothing as a “credit” in exchange for whatever they accept as collateral, whether the collateral is really worth anything or not. And if the debtor fails to pay it back, the Fed just creates more nothing to bail them out, as often as necessary. The AIG vicious circle, for instance, is a prime example.