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 Alexander (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 Reid (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 Thune (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.