Portions of the bill that are not offset are extensions to unemployment and FMAP.
"That is, the safety net provisions are not offset," Baucus said. "Everything else is offset."
The so-called 'doc fix' and extensions to expired tax breaks are offset. The package would only postpone Medicare payment cuts to doctors through November, making it a likely lame-duck session issue. The House passed a 19-month fix after paring it back from about three years.
Baucus also said there are modifications the tax increases on carried interest and S corporations, but did not offer details on the changes.
"We'll have more to say about those tomorrow," he said.
The measure also nixes the additional $25 a week in unemployment benefits checks that was approved by the economic stimulus in February 2009.
Senate Democratic leaders suffered a setback on the extender bill earlier on Wednesday when they could not secure the 60 votes needed to move forward on the bill.
The chamber voted 45-52 against the proposal with 12 Democrats opposing the bill.
Sen. Lamar AlexanderLamar AlexanderOvernight Regulation: Trump's Labor nominee hints at updating overtime rule Trump's Labor pick signals support for overtime pay hike Live coverage: Day three of Supreme Court nominee hearing MORE (R-Tenn.) said Democratic defections stemmed from members becoming very concerned about the first bill adding approximately $80 billion to the deficit.
"That was reflected in the vote today," he told reporters, adding that Republicans agree with "most of the policy [that] is in the bill."
Senate Majority Leader Harry ReidHarry ReidThis obscure Senate rule could let VP Mike Pence fully repeal ObamaCare once and for all Sharron Angle to challenge GOP rep in Nevada Fox's Watters asks Trump whom he would fire: Baldwin, Schumer or Zucker MORE (D-Nev.) needs at least some Republican support to pass the bill from his chamber, but it is unclear if the changes made to the bill will entice conservatives to support the new proposal.
"Senators are individuals and they'll cast their own votes," Alexander said. "I can't predict what they might do."
Tax lobbyists told The Hill that centrists senators are still not happy with the legislation, in part because of some of the tax changes included in the new version.
However, Sen. John ThuneJohn ThuneWeek ahead: Robocall crackdown tops FCC meeting agenda Here's how Congress can get people to live healthy lifestyles Ryan huddles with GOP factions on healthcare bill MORE (R-S.D.) said Democratic leaders are taking a "shooting gallery approach" in getting Republicans to support the bill by "picking off one or two" of them to back the proposal.
"I can't predict unanimity on our side," Thune said, adding, "But I can tell you that consensus about borrowing, debt and deficit spending is growing stronger in our caucus, and I think it is in the Democrats as well."
Vicki Needham contributed to this report.