Not necessarily. If you only need the text, you can click your text cursor anywhere into a running story and select “Export”, then select “Rich Text Export” in the “Format” drop down menu. Word can read RTF text as good (hum hum) as it can read its own files.
But it depends on what you are expecting … RTF export doesn't include any text or images that are in a frame of their own, and I'm not too sure about embedded images either. InDesign also has loads more text formatting options than Word does (oh — Word has “word underlining” … can't think of anything else that would be useful), and this formatting will get Lost in Translation, as will custom non-mapped glyphs, and — I think there was a question regarding that on the Adobe InDesign Forum — Word cannot handle large font families with more weights than “Regular” and “Bold”.
The Light Side, then, is both Paragraph and Character styles ought to translate to their Word counterparts, meaning, you can export to RTF, edit the text in Word using the same paragraph and character styles, then read back into ID and have your original style styling back. (Or so I've heard. I've never been tempted to try it — What Happens in InDesign, Stays in InDesign, is my credo. Well, one of them, anyway.)
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