Sen. Joseph Lieberman (I-Conn.), left, with Sen. Thomas Carper (D-Del.), speaks Wednesday about the future of the U.S. Postal Service. (Andrew Harrer/BLOOMBERG)

A bipartisan Senate bill introduced Wednesday would give the U.S. Postal Service about $7 billion to pay for employee buyouts and other debt, allow a renegotiation of postal worker health-care benefits and require two years of studies before ending Saturday mail deliveries.

The plan, a modified version of proposals previously introduced by Sens. Thomas R. Carper ­(D-Del.) and Susan Collins ­(R-Maine), will be considered by a Senate committee Wednesday.

The bill refunds about $7 billion that auditors agree the Postal Service has overpaid into federal worker retirement accounts. The money would be used in part to offer buyouts of up to $25,000 to as many as 100,000 eligible postal workers, with the rest of the funds put toward other debt.

Refunding the money “is not a bailout,” Sen. Joseph I. Lieberman (I-Conn.) said. “It’s the result of a legal analysis that everybody agrees with, that this was in fact an overpayment by the Postal Service” into the Federal Employee Retirement System.

House Republicans disagree. They consider any attempt to refund the Postal Service with money from federal retirement or health-care accounts would be a taxpayer-funded bailout.

The Senate bill also would scrap a 10-year payment schedule that requires the Postal Service to pay about $5.5 billion annually to prefund future worker retirements. The bill would spread out those payments over 40 years, significantly reducing the annual obligations that postal officials say cause much of the agency’s cash shortfalls. The Postal Service also would be allowed to renegotiate a new health-care plan with its major worker unions to help cut costs.

Short-term spending legislation passed last month by Congress gave USPS until Nov. 18 to make its annual prefunding payments. Aides said Wednesday that they did not know whether the Postal Service would get another extension or be forced to make the payment this month.

If the bill passes, plans to end Saturday mail deliveries would have to wait at least two more years until USPS and postal regulators further study the potential effects on customers and industries that rely on six-day mail deliveries.

The Postal Service also would have to scrap the delivery of mail to some doorside mailboxes in favor of sidewalk, curbside or centralized neighborhood boxes. The bill also would force the USPS to further study the effects of closing post offices and mail processing facilities — a move that postal officials said could save billions of dollars in operating costs.

“Without taking controversial steps like these, the Postal Service simply isn’t going to make it,” Lieberman said. “That would be terrible.”

Collins said that the bipartisan proposal — also backed by Sen. Scott Brown (R-Mass.) — is a more thoughtful, studied approach than the bill introduced last month by House Republicans.

The House proposal, introduced by Rep. Darrell Issa ­(R-Calif.), would establish a financial control board to overhaul postal finances — a move critics say could result in layoffs — not buyouts — of hundreds of thousands of postal workers.

Issa’s bill was approved by his House Oversight and Government Reform Committee last month, against the objections of Democrats who said it was too quickly considered and would unfairly target workers.

The Postal Service and postal labor unions said Wednesday that they are reviewing the legislation.

The National Association of Letter Carriers said the Senate bill “seems to embrace the postmaster general’s view that we must drastically downsize the Postal Service in order to save it.” The union called on lawmakers to save USPS in a way that “preserves jobs and encourages growth at a time when the economy is struggling.”

Industry groups representing some of the nation’s biggest mailers, including publishers, financial services firms and retailers, praised the proposal as a thoughtful bipartisan plan.