A Republican-sponsored tax reform plan (PDF) unveiled Wednesday could reduce federal income taxes for many Americans, though the details are sketchy on who would benefit most and who would pay more. 

The "Unified Framework for Fixing Our Broken Tax Code," released by the Senate Finance Committee, reduces the number of tax rates to three, nearly doubles the standard deduction, and makes more people eligible for child- and adult-care tax credits.

It also eliminates most other deductions, including those for state and local income taxes, but keeps deductions for mortgage interest and charitable contributions. The plan also eliminates the alternative minimum tax, or AMT, and the estate tax. 

"It’s a very general framework," says Howard Gleckman, senior fellow at the Tax Policy Center, a think tank sponsored by the Brookings Institution and Urban Institute in Washington, D.C. "It leaves a number of important details until later. And it never says how we're going to pay for it."

Here's a look at the major changes being proposed and how they could affect you. 

Standard Deduction Nearly Doubles

The change: The standard deduction would be raised to $24,000 from $12,700 for married couples filing jointly. For single taxpayers and married couples filing separately, the standard deduction would rise to $12,000 from $6,350. 

But the personal exemption, which is currently $4,050 per person, would now be included in the standard deduction, so the actual increase isn't as big as it appears. 

Who it affects:  Anyone whose total tax deductions (line 40 of your 2016 Form 1040) were less than $24,000 for a married couple or $12,000 for a single filer. 

With the higher standard deduction, many people may no longer have to pay federal income taxes at all.

"That’s going to push a ton of people out of the income tax system entirely," says Jeremy Scott, vice president of editorial operations at Tax Analysts, a nonpartisan tax publisher based in Falls Church, Va. 

You probably should still file a return even if you're no longer paying taxes, Scott adds. Filing a return allows you to take advantage of things like the earned income tax credit, a refundable credit for lower-income earners.  

3 Tax Rates Instead of 7

Tax rates would be reduced to three—12 percent, 25 percent, and 35 percent—from the current seven. The lowest rate would rise to 12 percent from 10 percent, and the highest earners would see their maximum tax rate fall to 35 percent from the current 39.6 percent.

The proposal says a higher rate could still be reimposed.

"An additional top rate may apply to the highest-income taxpayers to ensure that the reformed tax code is at least as progressive as the existing tax code and does not shift the tax burden from high-income to lower- and middle-income taxpayers," the plan says.

Who it affects: Without releasing the tax brackets—the income level at which one tax rate ends and another begins—it's impossible to know who will win and who will lose from this change.

But even with a higher, 12 percent tax rate, those paying that rate probably would end up paying less overall because of the higher standard deduction, Scott says.

Even with the potential addition of a top rate, higher earners could still come out ahead, Gleckman says. That's because of business-related tax breaks introduced by the bill, including a reduction in the income tax on family-owned "pass-through" entities such as hedge funds, medical offices, and legal firms.

Income from those businesses is reported on owners' individual returns, not on business returns. So wealthy businesspeople who might otherwise pay at least 35 percent on that income would pay 25 percent, Gleckman notes.

"Our sense is the clearest beneficiaries are higher income people," he says. 

Most Itemized Deductions Ended

The change: The GOP plan attempts to simplify the tax code by eliminating most itemized deductions except those for mortgage interest payments and charitable contributions. 

Who it affects: Taxpayers who currently deduct state and local income, property, sales, and other types of tax could no longer do so on their federal tax returns.

Upper-middle-class residents in high-tax states like California, Massachusetts, New Jersey, and New York would be hit hardest. Of the 10 Congressional districts that claim the highest state and local tax deductions—also known as SALT deductions—eight are represented by Democrats, Bloomberg reports.

For less wealthy residents of those states, however, the doubling of the standard deduction may offset the loss of the state and local tax deduction.  

The GOP plan doesn't specifically spell out what happens to other tax breaks such as the deduction for higher-education and retirement savings as well as miscellaneous expenses such as medical care. But the Finance Committee document does say that the plan "retains tax benefits that encourage work, higher education and retirement security."

The details will have to be worked out by Congress.

"The committees are encouraged to simplify these benefits to improve their efficiency and effectiveness," the GOP document says. "Tax reform will aim to maintain or raise retirement plan participation of workers and the resources available for retirement."

Child Tax Credit Expanded

The change: More taxpayers would be eligible for the child tax credit, which is currently at $1,000 per child. The plan gave no details on what the new income limits would be for the credit, however.

Still, some married couples would no longer be excluded from taking the credit because of their income. Currently single people with adjusted gross income of up to $75,000 can take advantage of the credit, but married couples with double that—$150,000—are disqualified because eligibility for them phases out at $110,000. 

The plan also calls for a new, nonrefundable $500 tax credit for non-child dependents, to help cover the cost of caring for a dependent adult. No details were provided on who would be eligible.

Who it affects: More earners with dependent children and adults could benefit from this change. More upper-middle class married couples will be able to claim the tax credit as well.

AMT and Estate Tax Ended

The change: The proposal gets rid of the alternative minimum tax, an arcane tax initiated decades ago to penalize wealthy people claiming many deductions. The tax now affects many more Americans, including married households with taxable income of less than $85,000, and singles with income below $55,000.

The federal estate tax, which the plan called the "death tax," would be eliminated, as would a generation-skipping transfer tax. 

Who it affects: People in higher-tax states—including many of those who would lose out from the loss of state and local tax deduction—would benefit most if the AMT were to go away.

Proponents of the estate tax repeal maintain that many small farms suffer from this tax, which charges as much as 40 percent on inherited property. But opponents say there are less than 200 family farms affected and that the biggest beneficiaries will be very wealthy families inheriting estates worth $5.45 million or more. The generation-skipping transfer tax, which generally relates to estates being passed to grandchildren, affects many of the same families.

Impact on Tax Filing

While the plan attempts to simplify the tax system, analysts say many taxpayers would still have to go through the same process when they prepare and file their taxes. 

With the higher standard deduction, far more people would be able to determine easily through tax software or the IRS website whether they're eligible to file a simple 1040, 1040A or 1040EZ, without having to gather documentation to claim deductions, Scott noted.

But others would still have to go through a process of deciding whether to itemize or take the standard deduction. They would still have to gather documents, use tax software or visit a tax professional.

"This will not significantly change how people file," Scott says. "You’re going to have to do the same calculations. It's just the amount you owe will change and how you get to that amount will change."