CKEditor paste filter is not working for content pasted from Word

Question

I'm looking for a way to filter content pasted into a CKEditor such that the paste filter is more restrictive than the active content filter. According to the documentation, a "paste filter" should do exactly that.

I've set up a simple jsfiddle to demonstrate. That fiddle is set with a paste filter of 'plain-text'

CKEDITOR.editorConfig = function(config) {
  config.pasteFilter = 'plain-text';
};
CKEDITOR.replace('editor1');

If I copy styled content from MS Word for Mac and paste it into the editor window, the styling is maintained. Based on the documentation, I expect it to be pasted as plain text. I've tried this in both Firefox and Chrome.

The fiddle is simply CKEditor 4.17.1 loaded from the CDN and a simple configuration. I must be doing something wrong or have mis-understood the docs.