NBC News: Trump already has a game plan, as well as individuals identified in states to help begin the process of getting him on the ballot.
Trump filed his voter registration paperwork Thursday, Cohen added.
He said Trump probably would use his substantial wealth to even the playing field with Obama's re-election campaign.
The move was disclosed 10 days after Trump announced he would not moderate a planned debate among 2012 Republican presidential candidates. All but two candidates declined to participate in Trump's proposed event.
Former Massachusetts Governor Mitt Romney, former Utah Governor Jon Huntsman, Texas Governor Rick Perry and U.S. Representatives Ron Paul and Michele Bachmann had said they would not attend the planned Trump-moderated debate. Former House of Representatives Speaker Newt Gingrich and former Senator Rick Santorum had agreed to take part.