ST. PAUL, Minn. (AP) -

A third piece of the Minnesota Legislature's income tax puzzle is falling into place.

The Senate Taxes Committee planned Tuesday to detail its tax bill. The key unknown is the scope of a proposed new top income tax tier.

A so-called fourth tier is almost certain to be enacted this year. But Democrats, who control the Legislature and the governor's office, differ on the income level and rate to apply.

Gov. Mark Dayton has proposed a new 9.85 percent tax rate on income above $250,000 for married couples and $150,000 for single filers. In the House, the income tax wouldn't kick in as soon and the permanent tax rate is lower than the governor's recommendation. But House Democrats would also tack a 4 percentage point surcharge on incomes above $500,000.