Question for Q on Federal Reserve

As you point out in an earlier post going back to November that the Fed is privately owned and not on US govt property. Over the years Fed chairmen (chairpersons!) have rejected the notion of a governmental audit.

As a financefag I know enough about the Fed as their role as the fiscal arm of the US treasury . They have always held around 10-15% of each govt bond auction on their balance sheet. The recent QE ballooned their balance sheet into the 4 trillion range. The interest earned on those bonds is supposed to be remitted to the Treasury after deduction of the Fed's operating expenses. Except without an audit how does anyone know how much that's supposed to be.

On each trillion dollars of balance sheet even a modest 2% is $20 billion in interest. I've "heard" that some of that interest income is used to fund black ops around the globe (and as a byproduct does not have to appear in any congressional budget requests on the part of any of the clandestine three letter agencies). Any thoughts on the lack of transparency?