$5-Billion was Debtor's-fiction-value $20-Billion is-2011-value
Don't try to combine the $5 billion NOL fiction with the $20 Billion NOL reality. Your math will get screwy.
Net Operating losses directly offset capital gains. Did you ever lose money on a stock trade, but made money on another one? The loss offsets the gain and you pay no tax because you made no money. Here, a company with $20 Billion in Net Operating Losses needs to be purchased by a company with $20 Billion in capital gains so THAT COMPANY GETS TO KEEP THE $20 bILLION.