It's not really possible to link a Word document to an InDesign document and expect that the formatting will stay up-to-date. If you go back to the Word document to make changes, when you return to InDesign to update the link, any formatting applied in InDesign will be discarded. That's just the way it is.
You should explore an InCopy workflow instead. This document describes the workflow. While it's written for CS5, it has not essentially changed in CS6 or later:
As others have said it is correct.
But I would strongly recommend not to use Styles imported from Word. Create your own styles in InDesign. You can map Word Styles to InDesign when you import a Word document and save this mapping.