I rarely watch the news, but when I do, I usually watch Newsy which proudly claims to be anti-partisan, and I think they generally live up to that standard.
Admittedly, they orient themselves towards my generation, and their main reporters and anchors are all between 20-40 years old. I even saw one of them on a dating site (she didn't match with me).... If you watch and get an impression that they lean liberal, I would understand that, though.