Tag Attributes - Footnotes
Footnotes, consisting of explanatory text, can be attached to an XBRL tag. Not all taxonomies require the use of footnotes and footnotes should not be used unless specifically instructed to do so or to clear validation failures.
Example, in the South African CIPC taxonomy, you are required to insert a footnote if the value of your Turnover or Liabilities tag is 0:
Adding a Footnote
To clear this validation rule, add a footnote to the tag in the XBRL Tags ribbon.