The Senate passed a Republican-authored budget plan early on Friday that seeks $5.1 trillion in domestic spending cuts over 10 years while boosting military funding.
The 52-46 vote on the non-binding budget resolution put Congress on a path to complete its first full budget in six years. It came at the end of a marathon 18-hour session that saw approval of dozens of amendments ranging from Iran sanctions to carbon emissions and immigration policies.
Two Republican senators who are running or considering running for president, Ted Cruz and Rand Paul, voted against their party's budget plan, which is similar to one passed by House Republicans on Wednesday.
In addition to aiming to eliminate deficits within 10 years, both documents seek to ease the path for a repeal or replacement of President Barack Obama's signature health care reform law.
But differences between the two documents still need to be worked out and a combined budget passed next month by both chambers. Doing so would allow Republicans to invoke parliamentary rules to repeal "Obamacare" with a simple majority in the Senate rather than a tough-to-achieve 60 vote threshold.
Under the convoluted U.S. spending process, the budgets do not become law, but influence government agency funding bills later in the year. They also showcase the fiscal vision for Republicans, who now control both Houses of Congress for the first time since 2006 and are eager to demonstrate their ability to govern.
"This balanced budget is an important first step to help Washington live within its means, just like hardworking families have to do every day," said Republican Senate Budget Chairman Mike Enzi.
He added that once a final budget is passed lawmakers would begin to work to find alternate savings that would allow them to ease statutory budget caps on military and domestic programs.
The Senate budget seeks to eliminate U.S. deficits by 2025 without raising taxes through deep cuts to social safety net programs, investments in transportation and education and other domestic programs.
At the same time, it proposes to boost defense spending by adding about $38 billion to an off-budget war funding account, and offers core Pentagon budget increases in subsequent years.
More than 50 non-binding amendments were considered on Thursday and Friday in an open "vote-a-rama" process that allowed senators to promote pet causes or try to force opposition members into votes that may be used in campaign ads.
Republicans passed a symbolic roll-back of the Obama administration's carbon emissions rules for power plants, while a Democratic proposal to recognize climate change risks for the military won approval.
Another Democratic amendment to let all Americans earn paid sick leave passed with a surprisingly strong 61 votes, with support from 14 Republicans. The Senate also voted unanimously to make it easier to reimpose sanctions if Iran violates any nuclear deal.
(Reporting by David Lawder; Editing by Tom Heneghan)