I do outline for most of my stories, but what kind of outline I make and how detailed it gets depends on the story. I have some outlines that are chapter by chapter or part by part, for Secrets of the Heart and my two collaborations, but usually I'm more of a timeline person.
My Curtain Call outline is basically a timeline, with a bunch of research at the bottom. The way I'm writing that story is, I'm God of the story, and I get to decide what situations to put my characters in. But since they have free will, they get to decide how to react. So I have various points along the way that are planned out and set in stone, but how the characters get there and what happens in between is decided chapter by chapter, as I'm writing.
Then I have Guilty Roads, with no outline whatsoever, only an idea in my head of where I'm going with it. That scares me a little, but we'll see how it goes.