US budget hawks have labelled a plan to hike defence and domestic spending by hundreds of billions of dollars as a debt-ballooning "monstrosity".
In a rare show of bipartisanship, Republican Senate leader Mitch McConnell and Democratic counterpart Chuck Schumer agreed the two-year pact.
The bill is expected to clear the Senate comfortably, but face opposition in the House of Representatives.
It comes on the eve of a deadline to avert another government shutdown.
Congress has to reach a deal before government funding runs out at midnight on Thursday, when a one-month spending bill is set to expire.
Both Democrats and Republicans in the House of Representatives have voiced disapproval of the bipartisan bill.
What's in the bill?
White House legislative affairs director Marc Short said the package would increase spending by "just shy" of $300bn.
The Washington Post puts the figure at half a trillion dollars.
The Senate bill, which has not yet been publicly unveiled, reportedly increases defence spending by $80bn in the first fiscal year and $85bn in the second.
Non-defence spending, such as a programme to provide health insurance for children, would reportedly increase by $63bn this year, and $68bn next year.
(Published by BBC - February 7, 2018)