What will happen if my bank goes bankrupt?

What will happen to my money if E*Trade declares bankruptcy ? I have a few bank account elsewhere, but the majority of my money is help in various E*trade accounts. This includes checking, savings, brokerage, and CDs. I'm aware that the money in the banking arm is FDIC insured, but what does that really mean? Is all of my money insured? Will it all go away if E*Trade goes under? Any sort of real world explanations and advice would be appreciated.