Democrats in the U.S. House of Representatives unveiled a broad healthcare overhaul on Thursday that would transform the insurance market, create a government-run insurance plan and levy new taxes on the rich.

Weeks of tough, closed-door negotiations to merge three pending House healthcare bills produced a 1,990-page measure that would cost an estimated $894 billion over 10 years -- below President Barack Obama's target of $900 billion -- and reduce the deficit by $30 billion over the same period.

"Today we are about to deliver on the promise of making affordable, quality health care available for all Americans," House Speaker Nancy Pelosi said in a ceremony on the steps of the U.S. Capitol.

But the measure faced unanimous opposition from Republicans