If you are doing file>export,then select “save as type” = “Microsoft RTF”. You can name your file whatever.doc, and it will open in MSWord. Choosing RTF will preserve the font styles and formatting. (In any conversion from one software product to another, there may be an occasional formatting difference, though.)
If you’d like to consider a third-party solution we have an export utility for Lotus Notes / Domino which can export your documents directly to MS Word, PDF, HTML, MS Excel, MS Access, CSV and many other formats.