Mnuchin and Cohn's outline included a few vague hints at ways to raise revenue. It promised "targeted tax breaks" for individuals and "special interest" breaks for corporations. It promised to preserve the home mortgage interest and charitable deductions but implied that all other itemized deductions (such as for state and local taxes) were gone.
In the 2016 campaign, the Trump campaign also floated a few other ways to raise revenue that didn't make it into the administration outline, like repealing "head of household" filing status for single parents, repealing personal exemptions for taxpayers and their dependents, still subjecting "large" pass-through businesses to individual tax rates, and imposing capital gains tax on certain wealthy estates upon death, so that valuable assets that were never taxed in a person's life could be taxed.
The TPC paper takes all these together and tries its best to estimate what they'd raise. Put all together, they raise about $4.3 trillion over 10 years. That's no small amount — but it's also not nearly enough to pay for $7.8 trillion in cuts. Further, it's worth asking whether these are revenue raisers that the Trump administration is actually willing to countenance. Would Donald Trump, a wealthy person living in a high-tax liberal state, really do away with the state and local tax deduction, which predominantly helps people like him? Would he really raise taxes on wealthy estates like his own?
Usually, when challenged on the numbers for its tax proposals, the Trump administration has insisted that they'll lead to large-scale economic growth, which can largely offset the cost. The TPC finds that this isn't the case. The total plan, incorporating both revenue raisers and tax cuts, would cost $3.5 trillion over 10 years before taking economic growth into account, and $3.4 trillion after you take it into account. You only raise $108.9 billion from growth effects.
The revenue raisers also serve to make Trump's plan even more regressive. If you just look at the tax cuts he's proposing, 60.9 percent of the benefits go to the top 1 percent of Americans. That's a pretty astonishing tilt toward the rich. But if you look at the combined effects of the cuts and the revenue raisers, 76.3 percent of the benefits go to the top 1 percent, and 94.8 percent go to the top 5 percent. Getting rid of head of household filing status and personal exemptions are tax increases that overwhelmingly hit middle-class people and don't hurt the rich much at all, especially since the personal exemption currently phases out for rich taxpayers.
"We emphasize that we are not analyzing the Trump administration's tax plan: the released outline contains too many unknowns to do so," TPC emphasizes. It had to fill in a lot of vague parts of Trump's plan to produce numbers. But the report does indicate that the Trump plan will likely be very regressive, and very expensive.