WASHINGTON — Ready to end a bruising election-year fight, negotiators on Capitol Hill sealed an agreement late Wednesday on legislation to renew a payroll tax cut for 160 million workers and jobless benefits for millions more.

Sen. Max Baucus, D-Mont., announced the agreement, capping a long day of wrangling over final details of the bill, a top priority of President Obama. The announcement paved the way for House and Senate votes  this week.

The $150 billion measure represents a tactical retreat for Republicans, who were generally unenthusiastic about the legislation but eager to move beyond the issue. With the campaign season starting, they don’t want Obama and Democrats in Congress to be able to claim that the GOP was standing in the way of a middle-class tax cut.

The bill would continue a 2 percentage-point cut in the Social Security payroll tax through 2012, renew jobless benefits averaging about $300 a week for people languishing for long periods on unemployment rolls, and protect doctors from a huge cut in Medicare reimbursements.

The measure carries a price tag of roughly $150 billion over the coming year, partly financed by new auctions of telecommunications spectrum to wireless companies and by requiring newly hired federal workers to contribute 2.3 percent of their salary toward their traditional defined-benefit pensions. The pension provision would raise $15 billion.