1 Trillion is on the low end in my opinion. US housing devaluations will probably hit half that by itself. I'd have to go back and add some numbers but seems like banks are half way there already in mortgage related write downs. Throw in the costs related to what these financial products have done to various credit markets and there is a case that there has been a trillion in damage already. I've seen ranges from 2-10 Trillion in total cost.