In my heart of hearts, I am a pantser, but I need outlines these days XD.
I tend to do my outlines in stages. The first stage is something really basic and very vague--like just chapter titles as stand-ins for beats to give me an idea of where it's going. As you say, a sentence can produce quite a bit.
For me actually find that if I do any more than that on a full outline, I run the risk of either:
A) planning too much by forcing in things that actually, in context, don't work for the character/event/pacing (and thereby obsoleting a lot of the work I've done on the rest of the outline).
Or B) getting that feeling of: Well, I finished the story for myself, so I don't really want to write it anymore. XD
Recently, I've been trying more detailed outlines because I'm usually working on 2-3 [serial] stories simultaneously. Without functional outlines, I risk losing my thoughts or place. With these though, I usually just plan to the end of the arc in explicit detail, so it's just a matter of filling in the details for the word count, and if I have to throw out the outline because of a snag I haven't wasted too much time XD.