So back to your original statement, if they only have $8 billion in debt and there is $30 billion settlement, the $30 - 8 = $22 billion + $4 billion in cash = $26 billion - $3.5 billion to pay the preffereds = $22.5 billion / 1.8 outstanding shares = a value of commons equaling $12.50 .
So, how do you figure that there wouldn't be any value left for the common equity ?