Senate Republican leaders plan to unveil their tax reform legislation in a closed door meeting with GOP senators Thursday morning, according to Majority Whip John Cornyn, R-Texas.

“We are going to walk through the bill with the Republican conference at 11:30 tomorrow morning, so it will be out there," Cornyn said after meeting with GOP lawmakers on Wednesday.

The Senate bill, authored by Finance Committee Chairman Orrin Hatch, R-Utah, is expected to have significant differences compared to the House tax plan that is now under consideration in the Ways and Means Committee.

Way and Means Chairman Kevin Brady, R-Texas, said his panel would finish marking up the bill Thursday, readying it for floor consideration by next week.

The two chambers will have to come to an agreement on a compromise bill if they both pass separate versions. The differences are likely to be significant.

The Senate bill, for example, may maintain the estate tax while raising the cap. The House bill phases out the estate tax.

The Senate bill may maintain certain popular tax deductions that are so far not included in the House version, and could make changes to "pass through" rates so that benefits increase for small businesses.

The Senate bill may also phase in the cuts to the corporate tax rates rather than implement the reduced rate immediately.