In order to affect monetary policy, the Fed now pays 4.9% interest[1] on $3.03trn of reserve balances[2], which is now costing them approx $150bn/yr run rate. Just 12 months ago they paid 0.15%.
This $150bn cost is a consequence of quantitative easing massively expanding reserve balances, and those reserve balances still existing in a period of high inflation which is being fought with high interest rates. The obvious solution is quantitive tightening to shrink the quantity of reserves, however there's justifiable concern about the effects this could have on the still-fragile banking system.
This is real money to the US taxpayer. The Fed used to remit $100bn a year to the US treasury, which it has now stopped doing. Instead, the Fed is sending this money to the US commercial banks which hold US reserves.