I am unable to locate current numbers for the total amount of discretionary and (mandatory) non-discretionary federal spending. Some of the estimates I have seen range from $4.4T to nearly $6T in spending.
A lot depends on interest rates too. The higher the interest rates the more the government pays on its debt.
I'm pretty sure that the Treasury converted many of its long term bonds to short term bonds with interest rates around 1-2%. This implies that the government will be rolling over its debt more frequently which will hurt when interest rates increase (if that ever happens).