The Senate version of the Republican tax bill will partially retain the alternative minimum tax, a change made Friday to help pay for promises made to GOP senators to secure their votes.

The retained alternative minimum tax will help pay for maintaining a property tax deduction, as well as bigger tax breaks for small businesses. But it will come at the cost of simplification.

"They won't be repealed," Sen. Mike Rounds, R-S.D., said of the individual and corporate minimum taxes. "There will be a lot of modifications to them."

"The bill's probably better now than what it was earlier," Rounds added.

It wasn't clear how much revenue would be raised with the change. But Republicans had to keep the total tax cut below $1.5 trillion over 10 years for procedural reasons.

Another revenue-raiser added to the bill at the last minute as leaders sought to pass it Friday was to increase the size of the one-time tax imposed on multinationals' untaxed earnings held overseas.