I don't understand the cost either, apparently it only costs around a billion dollars to build a skyscraper? The Burj Khalifa only cost one and a half billion d

I don't understand the cost either, apparently it only costs around a billion dollars to build a skyscraper? The Burj Khalifa only cost one and a half billion dollars when completed in 2010. I don't know that there's criminal activity here, but the cost of this is rather surprising to me. I knew the Federal Reserve was being renovated, but I thought it was something closer to a hundred million dollars.