As everyone knows (since the data is public [3]), in the most recent week the Fed's balance sheet rose to a record $3.646 trillion, an increase of $61 billion in the past week, and a record increase of $813 billion over the past year, a whopping 30% rise in the balance sheet in 12 short months. What may not be known is the exact distribution of Fed Treasury holdings by maturity. So without further ado, here it is. Of note, observe that what once was a predominantly 'short-end' balance sheet (consisting mostly of no-coupon, money equivalent Bills), has become almost entirely a "5 and over" current coupon carry affair. Which also is why the Fed now takes over the entire bond market at a rate of 0.25% per week.
[4]
Source: Goldman