So, let's see if I get this right. You honestly believe that if Fannie Mae is released from conservatorship they somehow don't have to pay the $3 B in taxes? I just spit coffee on my keyboard.
Fannie earns $10 B per year in income, all of which went to the government via the sweep. If the sweep ends, Fannie could possibly keep all that $10 B as income. If Fannie resumes paying $3 B in annual dividends, as was their historical norm, Fannie's income is $7 B.
This should not be hard to comprehend with ten fingers, right?