Unfortunately, Id doesn't offer a "Paste Special" option so Copy/Paste looses all formatting. This isn't Word's fault; it's Adobe's.
When I need to do this, I edit the Word doc to remove all unwanted portions and save that as either a DOC or DOCX. I can then DragonDrop the new file into an Id document. This way, formatting survives, at least all the formatting I've needed. There might be some thngs that aren't supported (I suspect most or all graphics and artwork), but I've yet to actually need to import anything other than text. When I've needed graphics I've always imported those separately from the original source artwork.