Zonal, Scented, Seed and Ivy geraniums are the most likely to winter successfully indoors. They really should be considered just a pot crop that provides a breathtaking display of bloom for several weeks. Often you will read or hear about storing geraniums bare root and dormant in the basement overwinter. The success of this method will depend on the place you have to store them. When people had cold cellars or pump rooms, it worked quite well.
Most modern basements are much too dry and too warm.
To try this method, dig the plants up before a killing frost in the fall. Cut the branches back about half way. Remove as much of the dirt from the roots as possible. You will have to do this carefully, because geraniums are rather brittle. At this point, they were traditionally hung from the rafters until spring.