As Donald Trump promised to dramatically cut federal income taxes for all Americans earlier this week, one question kept popping up: How exactly would the Republican presidential hopeful pay for these massive cuts?

Trump has said his tax cuts for individuals and corporations would immediately spark dramatic economic growth -- perhaps as high as 6 percent per year, even though for the past five years that rate has not topped 2.5 percent. Tax experts caution that Trump's proposed tax cuts could add trillions of dollars to the national deficit over a decade.

Trump says that won't happen because he also plans to make "tremendous cuts" to the federal budget. During an interview with CNN's Don Lemon that aired Wednesday night, Trump said that in the coming weeks he will identify "outrageous" and "incredible" federal expenses that he would reduce, cut or renegotiate. That would likely include cutting "huge sections" of the departments of education and environmental protection, he said. Trump estimated that the U.S. loses "tens of billions of dollars" because of theft, incompetence and wasteful spending.

"So here's the thing: There's tremendous cutting that goes with my tax plan that I haven't talked about yet, but that will be phase two," Trump said in the interview. "So we're going to have a government that's going to be much leaner, much better, much meaner, but it's going to be meaner in the sense... of it's going to be efficient."

Trump said that unlike his Republican rivals -- especially retired neurosurgeon Ben Carson -- his business experience will allow him to make these cuts and boost the economy, even though some tax and budget experts are skeptical it can be done.

"I have one of the great scalpels in history," Trump said. "Now, it's different from Ben Carson's scalpel -- who's an excellent doctor -- but I have a scalpel for business."