Word doesn't have this functionality built in. However, you could use a macro to create a revisions table with, say, two columns - one for additions, the other for deletions. Of course, there are other kinds of revisions, such as formatting changes, that you might want to add to the output.
For a macro to export details of the changes to Excel, see:
http://answers.microsoft.com/en-us/o...f-8dc609cc75af