I could be wrong but I think that $250bil would be offset with short term borrowings. Also the MBS portfolio I think is where most of their income comes from. It will take about 6 years for them to get to current levels at a 15% reduction per year.
Interesting idea but I don't think a net $250 bil will be available to recapitalize anything. Keep in mind their net worth goes ZERO by 2018. I would say the thinking is $250 bil is more to provide operating capital through the wind down.