The House and Senate compromise spending measure would outline how three-quarters of the federal government, including the Defense Department, spend nearly $1 trillion through Sept. 30 when the fiscal year ends, the aides told The Washington Post.
Spending for the other quarter was settled Nov. 17, when lawmakers approved a $130.4 billion measure to fund five Cabinet departments -- Agriculture, Commerce, Housing and Urban Development, Justice and Transportation.
That bill, approved with a bipartisan majority, also provided temporary funding for the rest of government through Friday.
The progress House and Senate appropriations committee members made during the weekend could still face a last-minute snag, the aides told the Post. Negotiators were dealing with politically charged policy proposals, including those involving abortion rights, healthcare reform and environmental regulations.
But lawmakers were optimistic the progress would lead to a workable compromise, the aides said.
The agreement would come as lawmakers remained in a bitter fight over extending the payroll tax used to fund Social Security.
The latest GOP proposal would link the tax-cut extension, which President Barack Obama favors, to Republican priorities, including a measure to speed the construction of the controversial Keystone XL oil pipeline system from Canada to the Gulf Coast.
Senate Minority Leader Mitch McConnell, R-Ky., told "Fox News Sunday" "a significant number of Democrats" support construction of the 1,700-mile pipeline and would vote for the Republican bill.
"This has bipartisan support," he said.
But Senate Budget Committee member Lindsey Graham, R-S.C., told NBC's "Meet the Press" the pipeline was "probably not going to sell" -- although neither would the "idea of taxing one group to pay for a tax cut for another," referring to Senate Democrats' plan to pay for the cut by adding a 3.25 percent tax on gross income over $1 million for single filers and married couples filing jointly.
Graham predicted Congress would find a way of brokering a different bipartisan compromise to extend the tax cut, under which Social Security would not lose money.
Congress must also deal with other issues before adjourning for the winter holidays, including how to avert a scheduled deep cut in doctor reimbursement rates under Medicare and whether to extend benefits for the long-term unemployed. The jobless benefits are to begin expiring early next year, affecting 2 million people by mid-February.