The SEC has made DRAFT Form SD taxonomy files available for public comment. The taxonomy relates to new disclosures required by the Dodd-Frank Act. (This Compliance Week article provides good background information if you are interested in that.)
What is the most interesting about this draft is that it provides insight as to where the SEC, and most likely the US GAAP Taxonomy is likely headed.
One thing which I had mentioned before is that the US GAAP Taxonomy was going to stop using [Domain] within the set of [Member]s of an [Axis]. Rather what was a [Domain] would now be simply and more appropriately a [Member]. This Form SD taxonomy does exactly that. In fact, the SD taxonomy does this for two of the taxonomies used by the US GAAP Taxonomy, the DEI and the Countries taxonomy.
For example, you can see from this screen shot that the SEC changed the concept name "dei:EntityDomain" which has the standard label of "Entity [Domain]" in the DEI taxonomy to the standard label of "All Entities [Member]" in this draft taxonomy as can be seen in this screen shot.
The same is true of the member "country:AllCountriesDomain" with the label of "All Countries [Domain]" which was changed to "All Countries [Member]" in this draft taxonomy.
As I have pointed out before, the IFRS taxonomy is also going down this route. This is only one of many nice clues provided by the SEC to help one understand where things are headed.
Something to watch out for which will likely cause a bug in software which was built to only work with the US GAAP Taxonomy (as compared to software designed to read XBRL in general); the draft Form SD taxonomy uses the "targetRole" within the definition linkbase. I am almost certain that the US GAAP Taxonomy does not make use of the targetRole. This will most likely cause some software to break. This is not an issue with the Form SD taxonomy, it is an issue of the software. Fully compliant XBRL processors will have no issues with this. Software which can only read the US GAAP Taxonomy might have issues.
The targetRole allows for the construction of modular taxonomies as opposed to having to repeat the same model of something over, and over, and over. It is a good modeling approach.
Take a good look at this taxonomy, it is highly likely that this is a sign of things to come from both the SEC and the US GAAP Taxonomy in my view.