It also increases the top tax rate for capital gains – the proceeds from the sale of an asset like a boat or stocks – to 25 percent from 20 percent. Mr. Biden had proposed essentially doubling that tax rate. The proposal would also provide $ 80 billion over the next 10 years to the Internal Revenue Service to strengthen tax enforcement, a provision that budget markers estimate would raise $ 200 billion.

And while Mr. Bates, the White House spokesman, said the outline project met Mr. Biden’s commitment to avoid raising taxes for Americans who earn less than $ 400,000, the document suggests increasing the tax rate on tobacco products and imposing a tax on other products that use nicotine, such as electronic cigarettes. This provision is expected to bring in $ 96 billion.

The document also describes the possible inclusion of provisions on drug pricing and changes to tax rules to “treat cryptocurrency the same as other financial instruments.”

The full committee has yet to release and push forward the text of the legislation, and it is not clear whether enough Democrats will pass the package in the House and Senate. In order to protect the economic package from Republican obstruction and pass it by simple majority, Democrats can only have three votes in the House and must remain united in the Senate.

In part because of deep divisions within the Democratic caucus over the scope and structure of the package, Representative Richard E. Neal of Massachusetts, chairman of the Ways and Means Committee, had remained remarkably enigmatic about his own preferences for legislation. . Ahead of this week’s hearings, the committee released key elements of the package, including an extension of monthly payments to families with children until 2025 and tax incentives for cleaner energy.

A series of dueling comments on Sunday highlighted the competing perspectives within the Democratic caucus, as West Virginia Senators Joe Manchin III, a key moderate, and Bernie Sanders, the Vermont independent who chairs the budget committee, have marked their positions in several television interviews.

Mr Manchin reiterated that he would not support the $ 3.5 trillion spending, claiming that New York’s Senator Chuck Schumer, the majority leader, “will not get my vote” on a package of this size. .