With a depository bank in the US, there is $100,000 of FDIC insurance. With a stock brokerage, there is $500,000 in SIPIC insurance. You will get paid 100 cents on the dollar, up to those levels, depending on which type of institution you're talking about. For amounts above that, one would be a general creditor, and that's not a happy place. However, I think every effort would be made to make a Bear Stearns like deal, if at all possible.
I do not have a handle on how long it will take to collect on that insurance.