Political donations from business people at that level tend to be spread among both parties.
He might even have donated to Ed Koch. You know, the democrat mayor of NYC. Think they were best buds? In “Art of the Deal” Trump called Koch corrupt and incompetent.
Trump viewed political donations as a waste mostly. But you do it when you have to deal with political parties to get jobs done. That’s how the game is played unfortunately, and Trump has said on the campaign trail he knows how the game is played, and that that is part of the problem when you want to get things done.
https://www.youtube.com/watch?v=rcUCLwWCihE