As an alternative, copying the text into a simple text editor ...
Instead of copying the Word text into an external simple editor you can switch the moodle editor to html mode (in which the moodle editor functions as a simple editor) and copy the text into there, then switch back to the wysiwyg mode and fix the formatting.
Another, possibly better, alternative is to save the word file as filtered html and copy/paste the text from there into the moodle editor. This preserves standard formatting (such as headings, italic, bold etc.) without the extra Word specific styles definitions (aka extra/legacy code).