Reporting styles break financial reports into patterns of reporting styles. I have reporting styles for US GAAP and IFRS. Reporting styles organize fundamental accounting concepts into different allowed relations that appear in financial reports. I don't make the reporting styles up, I simply identify the patterns of reporting styles within US GAAP and IFRS reports that have been submitted to the SEC.
I verify the fundamental accounting concept relations per each reporting style each quarter for both US GAAP and IFRS as of last quarter.
I am now going one layer deeper within reports, what concepts are used within roll ups to the fundamental accounting concepts.
So, consider this reporting style: COMID-BSC-CF1-ISM-IEMIB-OILY-SPEC6. This same style is used in US GAAP and in IFRS. The model structure is essentially identical. There are some minor differences but for all practical purposes, they are the same.
Here are the mappings of the fundamental accounting concepts to the US GAAP and IFRS XBRL Taxonomy concepts: US GAAP | IFRS.
If you notice those mappings there is a link for all the XBRL concepts, US GAAP or IFRS. For example, us-gaap:Assets and ifrs-full:Assets have links. Click on the link and you will be taken to a web page that shows you how SEC filers are using those concepts relative to other concepts.
So, for example, if you click on us-gaap:Assetsyou see the 532 different concepts that public compainies used as line items that contribute to the total "us-gaap:Assets" in SEC filings. Note that this list includes 100% of the companies that use the COMID-BSC-CF1-ISM-IEMIB-OILY-SPEC6 reporting style. Here is the same information for ifrs-full:Assets. There are 270 different concepts that are used within roll ups of "ifrs-full:Assets". Now, for IFRS I am using all 339 filings. Currently I am experimenting to see what gives me the based information. It seems like doing the breakdowns by reporting style is best.
I also created a web service that provides this information for US GAAP and IFRS. That can be useful to those creating reports. I am not going to go into detail on this.
So, I am finding some interesting things. Consider the roll up of the components of concept Gross Profit. Here that is for US GAAP and for IFRS. If you look at either of those breakdowns of concepts you see the same thing for US GAAP and for IFRS. You see that most reports contain "Revenues" and "Cost of Revenues", which you would expect, and then you see pretty much odds-and-ends being reported.
Now, I have to do some additional analysis to figure out exactly what I am seeing. I think I am seeing some reporting inconsistencies, some missing taxonomy concepts, and errors filers are making creating extension concept which they really should be be creating.
Here are some clear errors. The US GAAP XBRL Taxonomy has a concept us-gaap:NoncurrentAssets. It also has the concept us-gaap:AssetsNoncurrent. Those concepts mean two different things. I think what is going on is that a few filers are providing detailed breakdowns of us-gaap:NoncurrentAssets in their geographic area disclosure.
Here are some clear errors:
If you find some interesting errors when you fiddle with this tool please let me or the SEC or ESMA or FASB or IASB know.
This PDF walks you through a presentation of this information.