OK. You do that, and you get a list of every style used, including the standard styles which have been slightly modified.
I had to take an MS Word document a few years ago which had been hacked together from several different documents, and do some work on it. When looking at the styles, each time one of the source documents had been modified, or the template changed, and then parts cut out and pasted together, you got another variant of the same style. In the list of styles, I had about 60 listed, many of which, from their name, should have been the same style.
It took me the best part of a week to trawl through the document, eliminating the minor variations, and consolidating the styles together. I got the number of used styles down to about a dozen.
This is not necessarily a problem with Word, but in the fact that most people who use word processors that use styles don't actually know how to use styles properly (I admit that I didn't know before cleaning this mess up).
In my view, this reinforces my view that ALL current word processors are too complex, and all most people need (even those writing quite complex documents) is something only a little more beefy than Wordpad.
I admit that I am biased, as I was an n/troff and runoff user before I came across Word 2 on DOS 2.1. I didn't like Word then, and I have to say, I would prefer not to use it now.