In Spain, testing 70,000 people for antibodies, actual Infection Fatality Rate is 1.16%
For the USA, if everyone gets exposed to reach herd immunity at 70%, we would expect about:
340 Million x .7 x 0.0116 = 2.76 Million deaths. IF, somehow, we can cut that in half or to 1/3 with better medical care, we still end up at 1.4 Million to 900,000 deaths.
One complexity in that: IF a lot of folks, like children, toss off the disease without antibody formation (say, by innate immunity, which IMHO is probable) those numbers could end up much lower.