Tagging with iXBRL

When tagging with iXBRL for SEC, use the following guidelines to tag facts correctly and provide the necessary information to meet iXBRL requirements.

Nil and Zero Facts

  • When there is a cell with content and you want to tag it as nil, make it a phantom fact in a non-printing section. In iXBRL, only empty cells can be tagged as nil.

  • Use only the following text for facts that are tagged as zero:

    • Zero or zero
    • No or no
    • None or none

    Tag nil and zero facts in non-printing sections

Accuracies and Multiple Facts

You must tag every use of a fact with its own individual accuracy.

  • Use chain linking to avoid duplicate fact errors.

  • The XBRL fact value must match the presented value in the document. You may need to change the accuracy in order to get the two to match. If they do not match, it can result in a duplicate fact error.


To avoid issues with duration tagging, make sure facts tagged with duration periods follow these guidelines:

  • When using words to describe a duration, such as ten, you must include a word that indicates the scale (years, months, days) in the text and the tag, such as ten years. If you tag only the numeric, such as ten with months outside the tag, this will not be a valid iXBRL fact and will result in an error.

Note: Do not use “weeks” for a duration because it is not currently supported by the SEC.

  • Only use a blank space between the month and time period, such as four years. Do not use a hyphen (-) between the number and the period, such as four-years. Other characters, like the hyphen, are not supported by the SEC.

  • Use a date link format for purely numeric durations in a table, such as 12, to make sure it is a valid iXBRL fact.

Tagging duration dates

Fact Breaks

  • Facts (not including text block tags) must not break between pages of the document. If they do, it results in an error.

  • Level 3 Text Blocks must be fully tagged in either a printing or a non-printing section. They cannot be partially tagged in a printing section and partially tagged in a non-printing section. A single text block that is partially tagged in both types of sections results in an error.

DEI and Cover Page Facts

  • FAST Act issued by the SEC requires iXBRL filers to tag all data on the cover pages for forms 8-K, 10-Q, 10-K, and 20-F and 40-F as annual reports.

Tagging DEI on cover page


When tagging with iXBRL in a 10Q or 10K SEC filing, the Exhibit Index document section must have a statement about XBRL tags embedded in the filing. For example, you can use the following text in the row referencing the interactive data file:

The instance document does not appear in the interactive data file because its XBRL tags are embedded within the inline XBRL document.

What’s Next