WASHINGTON — The House voted overwhelmingly Tuesday to restore full cost of living increases to pension benefits for younger military retirees, reversing course on controversial cuts approved by Congress less than two months ago.

After weeks of outrage by veterans groups, House lawmakers voted 326-90 to restore the pension benefits despite lingering disagreement over how to pay for the change.

Maine Rep. Mike Michaud, D-2nd District, voted for the bill. U.S. Rep. Chellie Pingree, D-1st District, has supported restoring the cost of living increases but missed the Tuesday afternoon vote because of “previously scheduled medical procedures that took longer than expected,” said spokesman Willy Ritch.

The House bill would reverse the changes to the cost of living adjustments that were built into a bipartisan budget bill that passed Congress in December. The $7 billion cost of the measure would be more than offset by extending pre-existing cuts in Medicare and other government programs for an additional year, through 2024.

Pentagon figures show that about 840,000 military retirees are under age 62 and would be affected by Congress’ earlier decision to reduce annual cost of living benefits one percentage point below the rate of inflation beginning in 2015. A sergeant first class who retires at age 42 after 20 years of service would lose roughly $72,000 over his or her lifetime under the change.

The bill now heads to the Senate, where Democrats and Republicans continued Tuesday to offer different fixes for the issue. Republicans rallied behind a proposal by New Hampshire Sen. Kelly Ayotte that would pay for the restoration by barring undocumented immigrants from receiving a federal tax credit. Democrats, meanwhile, insisted that Congress should have time to decide how best to pay for it.

Speaking during a Capitol news conference with Senate Democrats, Sen. Angus King, a Maine independent, said he has heard about 20 different proposals for how to pay for the pension fix. Congress should act now but take time to evaluate those proposals, King said.

“We can argue about how to pay for it at our leisure over the next two years, but we shouldn’t be arguing about it now,” King said. “The simplest, most straightforward thing is simply repeal it, get it off the books and make it a huge overwhelming vote. Because I think an important principle at stake here is trust in government, and particularly in the Congress of the United States.”

In the House, some Republicans were relieved that the measure was coming to a vote as a stand-alone bill, rather than as part of a measure to raise the debt limit as the Republican leadership initially proposed.

Several officials said Arkansas Rep. Tom Cotton, who is running for the Senate, had spoken out against combining the two in a meeting of the rank and file Monday night. They said the congressman noted that the proposed strategy meant lawmakers who wanted to oppose an unpopular debt limit increase would also be voting against the politically popular pension change at the same time.

Washington bureau chief Kevin Miller contributed to this report.