President Trump plans to unveil a tax cut blueprint on Wednesday that would apply a vastly reduced, 15 percent business tax rate not only to corporations but also to companies that now pay taxes through the personal income tax code — from mom-and-pop businesses to his own real estate empire, according to several people briefed on the proposal.

The package would also increase the standard deduction for individuals, providing a modest cut for middle-income people and simplifying the process of filing tax returns, according to people briefed on its details. That proposal is opposed by home builders and real estate agents, who fear it would diminish the importance of the mortgage interest deduction. And it is likely to necessitate eliminating or curbing other popular deductions, a politically risky pursuit.

As of late Tuesday, the plan did not include Mr. Trump’s promised $1 trillion infrastructure program, two of the people said, and it jettisoned a House Republican proposal to impose a substantial tax on imports, known as a border adjustment tax, which would have raised billions of dollars to help offset the cost of the cuts.

With that decision, Mr. Trump acceded to pressure from retailers and conservative advocacy groups, but the move could deepen the challenge of passing a broad tax overhaul in Congress, where concern about the swelling federal deficit runs high. His plan would put off the difficult part of a tax overhaul: closing loopholes and increasing other taxes to limit the impact of tax cuts on the budget deficit.