Postal worker unions gave the bill a mixed reaction. The National Association of Letter Carriers called it flawed because, among other things, it would cut services and jobs. The American Postal Workers Union agreed but said the bill would provide short-term relief to the Postal Service.

“There are some things that we don’t like in the bill, but it’s far better that something has passed rather than nothing,” said Cliff Guffey, president of the American Postal Workers Union.

The Postal Service, which objected to parts of the bill because it would limit the agency’s ability to close facilities and cut services, expressed disappointment in the vote. “If this bill were to become law, we would be back before the Congress within a few years requesting additional legislative reform,” the postmaster general, Patrick R. Donahoe, said in a written statement.

The bill would provide retirement incentives for nearly 100,000 of the post office’s 547,000 workers. It also would allow the agency to study the elimination of Saturday deliveries if it could not cut costs in the next two years, and it would free up the agency to offer a broader range of revenue sources like delivering beer and wine for retailers. The agency would also recoup more than $11 billion that it had overpaid into one of its pension funds.

Perhaps most significant, the bill would restructure the payments the agency makes into a health benefits fund for future retirees. Under a 2006 law, the agency has to pay $5.5 billion annually into the fund, which the Postal Service said had added $20 billion in debt to its balance sheet since 2007.