Google does not seem to actively advertise this, but they have a nice Chrome extension in their Chrome Web Store that allows for editing .doc, .docx, and other Microsoft file formats in their native forms.

Typically, when opening one of these Microsoft files, Google creates a copy in their native format (.gdoc or whatever the case may be). That is convenient, but sometimes I would prefer to maintain my documents in their original formats.

This extension/plugin for Chrome is a bit limited (it does not auto-save, and I've seen a few other quirks), but it has come in handy when I need to quickly edit Microsoft documents on my Mac.