“It’s a balanced and fair approach,” Murray said of her plan, adding, “This budget keeps the promises we’ve made to our seniors, our families, our veterans and our communities.”

Republicans fought back. “It’s obvious why they refused to release one for so many years,” said Senate Republican leader Mitch McConnell of Kentucky.

Murray’s budget is short on details; those will be fleshed out later. She’d cut $975 billion from expected spending while raising an equal amount in revenue.

The revenue would come from “closing loopholes” and cutting “unfair” tax breaks “for those who need it the least,” Murray said, “while locking in tax cuts for the middle class and low-income working families.”

The plan would include a legislative device called reconciliation that would make it easier to approve such changes.

Sen. Charles Grassley, R-Iowa, scoffed at the proposal. “There is nowhere near $1 trillion in loopholes,” he said.

The spending cuts would include $493 billion from domestic spending – including $275 billion in health care savings – and $240 billion from defense. Lower interest payments would save $242 billion.

The plan would add $100 billion in new spending to prod the economy, money that could be used for infrastructure repair, educational initiatives and other programs.

House Republicans were writing a very different budget Wednesday, without big revenue increases but with deeper spending cuts and a repeal of the 2010 health care law. They’d also change Medicare so that after 2024, seniors could get traditional Medicare or federal help for private insurance.

Murray made it clear that idea would go nowhere in the Senate. “We reject calls to dismantle or privatize Medicare” in that fashion, she said.

Anita Kumar contributed to this story.