Guido it is easier to see in the annual report, take 2020 10-K fannie, go to page 82/328, or search for 95.577
after the 3,960,490 liabilities, the 120,836 liabilities are added, since they retained 25,259 the "other deficit" is 95,577
so 95,577 + 25,259 = the 120,836 and the same thing can be seen for the year 2019
then if the 120,836 is written down the 120,836 will be deducted from the liabilities and the shareholders'equity will increase with the same amount as the liabilities are deducted in this case 25,259 + 120,836 = 146,095 (+Q1 5B = ~151B) with zero "other deficit" because of the write-down
we know CET1 in Q1 should have been $140, so without the SPS the surplus can be seen as 151-140 = 11
Fannie Mae estimates that, had the new enterprise regulatory capital framework’s requirements been applicable to the company as of March 31, 2021, it would have been required to hold approximately $190 billion in adjusted total capital, of which approximately $140 billion must be in the form of common equity tier 1 capital