Copyright ©2009 XBRL International Inc., All Rights Reserved.
This
version:
<http://www.xbrl.org/Specification/TCF/PWD-2009-03-31/TCF-PWD-2009-03-31.html>
Editor:
Maciej
Piechocki, IASC Foundation <mpiechocki@iasb.org>
Contributors:
Campbell Pryde, XBRL-US <campbell.pryde@xbrl.us>
Holger Obst, IASC Foundation <hobst@iasb.org.uk>
Atsushi Takeda, Japan
Financial Services Agency <atsushi.takeda@fsa.go.jp>
Masazumi Takahara, Fujitsu Research
Institute <mtakahara@jp.fujitsu.com>
Masatomo Goto, Fujitsu Laboratory of
America <mg@jp.fujitsu.com>
Hiroaki
Sakakibara, Fujitsu Limited <sakakibara@jp.fujitsu.com>
Makoto
Koizumi, Fujitsu Research Institute <koizumi.makoto@jp.fujitsu.com>
Jim
Richards, JDR and Associates <jdrassoc@iinet.net.au>
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This Request for Comment (RFC) describes practices that should be considered when developing XBRL taxonomies and specifically when deciding on the design choices for XBRL taxonomy architecture offered by XBRL specifications. Traditionally XBRL taxonomies satisfied the XBRL 2.1 specifications [XBRL 2.1] and later the XBRL Dimensions 1.0 specification [DIMENSIONS]. As experience and knowledge in XBRL taxonomy development has grown, so has the emergence of different taxonomy architectures around the world. While being a reassuring sign that XBRL adoption is on the rise, this diversity of XBRL taxonomy architectures may result in interoperability issues between XBRL implementations.
Existing XBRL specifications offer a variety of ways to achieve similar, though not identical, objectives in regards to the architecture of XBRL taxonomies. The Financial Reporting Taxonomies Architecture (FRTA) 1.0 [FRTA] was one of the first attempts to align the possibilities offered by XBRL specifications, and it still remains a benchmark for a number of financial reporting taxonomies worldwide. Since the publication of the FRTA 1.0 in April 2005 more practical experience has been gained, particularly in the area of XBRL Dimensions 1.0. This requires updating existing best practices for XBRL taxonomy architecture or establishing new best practices.
This RFC identifies and analyses the similarities and differences between
existing XBRL taxonomy architectures and solicits input from interested parties
who have relevant experience to bring to bear. This RFC will be the basis for
subsequently establishing best practices for the architecture of XBRL
taxonomies.
1 Goal
2 Executive Summary
2.1 TCF Sections
2.2 Comparison Criteria
2.3 Alignment Documentation
3 High Impact Areas - EDINET, IFRS, US GAAP
Comparison
3.1 Project Information
3.2 Technical Alignment
3.3 Domain Alignment
3.4 Extensions and Instances Guidelines
A References
B Intellectual property status (non-normative)
C Acknowledgements (non-normative)
D Document history (non-normative)
E Errata corrections in this document
1 Taxonomy Project Information, High Impact Criteria
The goal of this RFC is to identify the design decisions made in
architectures of XBRL taxonomies worldwide. This RFC introduces a comprehensive
comparison framework for three XBRL taxonomies (IFRS, EDINET and US GAAP) and
their architectures. It will provide other taxonomy developers with information
of the issues and choices available to them when developing their taxonomies.
The effort to provide a comprehensive comparison framework is a deliverable
of the Interoperable Taxonomy Architecture project (ITA). The ITA is a joint
initiative between the US SEC, the Japan FSA, the European Commission and the
IASC Foundation XBRL team, and aims to converge the
XBRL architectures of three taxonomies: EDINET, IFRS and US GAAP. In the
project's first stage, the three respective taxonomy developers agreed to
develop a comprehensive framework which would provide a basis for comparison of
the three taxonomy architectures. The result was the Taxonomy Comparison
Framework (TCF). The ITA project assumed a scope of analysis limited to
financial reporting in capital markets. Although XBRL taxonomies are often used
in other reporting scenarios (for example bank regulation, statistical
reporting or tax reporting) such usage of XBRL taxonomies was out of scope of
the ITA and thus is not analysed in the TCF.
The TCF consists of four different sections: Taxonomy Project Information, Technical Alignment, Domain Alignment and Extensions and Instance Guidelines Alignment:
A comprehensive set of criteria is defined and structured for each section.
For example, the Taxonomy Alignment section categorises
comparison criteria into physical definition, taxonomy design pattern, taxonomy
modelling, schema, linkbases,
presentation linkbase, calculation linkbase, definition linkbase, label
linkbase, reference linkbase, dimensions, and the use of new XBRL
specifications.
Within each broader category, a set of specific comparison criteria are
provided and each taxonomy is described according to
each criterion. For example, for the criterion "custom datatypes"
(4-2) in the Technical Alignment section the IFRS and EDINET taxonomies are not
defined, while the US GAAP taxonomy refers to specific datatypes
defined for the use in this taxonomy.
Each TCF provides an impact level of each criterion (none, low, medium and high impact). The impact level represents a consensus amongst the ITA project. There are also comments for the decided impact level, current status (aligned, not aligned, not used) and priority for actions (low, medium and high priority). For each criterion a placeholder for action points is provided. While impact level, current status and priority for actions are useful descriptors for the ITA project partners, they do not necessarily reflect the individual viewpoints of individual taxonomy developers.
This RFC only contains the criteria that have been assessed to have a high
impact level. The complete framework, fully populated with information about
each criterion for a set of taxonomies, is published as a spreadsheet due to
its size. Publishing in that format makes it more useful as a reference data
set. For further details, refer to the entire data set found at: Taxonomy
Comparison Spreadsheet
This section only summarizes a few of the important results from comparison
of the EDINET, IFRS and US GAAP taxonomy projects.
Taxonomy projects differ as to the expectation of whether extensions are
expected and what the source of those extensions will be. This has a high
impact on the design of the taxonomy.
|
# |
Criterion |
IFRS |
US GAAP |
EDINET |
|
1-1 |
XBRL
specifications at last release |
XBRL
2.1, XBRL Dimensions 1.0 |
XBRL
2.1, XBRL Dimensions 1.0 |
XBRL
2.1 |
|
1-2 |
Access
to the taxonomy |
Public
|
Public
|
public
|
|
1-11 |
Quality
assurance process, check rules & QA criteria |
Tests
incorporated in the development process, XQRT review and public review, tests
with all availabe tools. |
Over
200 tests run across all statements and disclosures on each incremental
build. |
design
is in progress |
|
3-3 |
Character
of taxonomy extensions |
Used
as core taxonomy (extenders) as well as reporting taxonomy (preparers). |
Internal
industry taxonomies (maintained by US SEC) and company specific extensions. An
extensive "Preparers Guide" (PG) focuses on the creation of
reusable extensions. |
Internal
23 industry extensions (maintained by JFSA) and company specific extensions.
External extensions done by NTA and TSE are expected. |
|
5-3 |
Strategy
for immediate release |
In
progress |
Final
release on 28 April 2008, with a new release of the taxonomy on January 31st
of every year. |
Design
is in progress |
Although there are several technical differences that have an impact on the interoperability
of taxonomies, whether the Dimensions specification is used, and the details of
how it is used, has high impact.
|
# |
Criterion |
IFRS |
US GAAP |
EDINET |
|
3-1 |
Usage
of tuples |
No
tuples used, modelled using one string document or
as an intersection table |
No
tuples; Tables (hypercubes) are highly constrained
by style rules. |
No
tuples adopted |
|
3-2 |
Intersection
tables |
20+
tables modelled by the means single element per
cell (all movemenets and reconciliations tables). |
Use
Dimension Tables |
Single
element for each cell (Statement of Change in Net Assets) |
|
3-3 |
Dimensional
patterns |
Used
for segment/scenario oriented use cases. |
Strongly
determined by style guide rules and transformations from the presentation
view. Hypercubes are Tables, Dimensions are Axes,
each Axis has one Domain child and that domain child has any number of Domain
Members. |
N/A |
|
5-1 |
Custom
arcroles |
No
custom arcroles |
We
have added arcroles for deprecated items in the
definition linkbase. Item - Deprecated |
5
custom arcroles: - Special - General - Gross - Net
- Gross - Allowance - Gross - AccumulatedDepreciation
- Gross - AccumulatedImpairmentLoss - Gross AccumulatedDepreciationAndImpairmentLoss |
|
8-1 |
Characteristics
of definition linkbase |
The
IFRS taxonomy uses definition linkbase to express dimensional relationships.
The "traditional" arcroles for definition
linkbase are not used. |
There
is one definition linkbase common to all GAAP statements, one common to all
GAAP disclosures and schedules. The only relationships there are dimensional. |
The
EDINET taxonomy uses definition linkbase to describe relationship of all
elements including: - Special - General - Gross - Net |
|
8-2 |
Usage
of definition linkbase for dimensions |
Yes |
Yes |
No |
|
8-3 |
Usage
of definition linkbase for non-dimensions |
No |
No
- But plan to implement in the future. |
Yes.
The EDINET taxonomy uses definition linkbase to describe relationship of all
accounting elements |
|
8-6 |
Custom
role / arcroles in definition linkbase |
None
custom arcroles |
None
on the published taxonomy. But will define in future. Currently have arc
roles for elements industry relationships in the development taxonomy. These
are used to generate the taxonomies by industry. |
There
are 5 custom arcroles for Definition Linkbase: -
Special - General - Gross - Net - Gross - Allowance - Gross - AccumulatedDepreciation - Gross - AccumulatedImpairmentLoss
- Gross AccumulatedDepreciationAndImpairmentLoss |
|
11-1 |
Characteristics
of Dimensions |
The
IFRS Taxonomy uses a definition linkbase to express dimensional
relationships. The modelling of axis information
with dimensions is introduced in cases where the information clearly belongs
to a context (can be either classified as a part of scenario or segment). The
IFRS Taxonomy defines dimensions and domain members for listed relationships,
thus using only explicit dimensions. The IFRS Taxonomy does not define hypercubes. |
There
are about 200 tables (hypercubes). Dimension is not
"New", by the way. |
No
dimensions are implemented in the EDINET taxonomy so far. |
|
11-3 |
Dimensional
contexts container (segment/scenario) |
Scenario |
Segments |
No
dimensions are implemented in the EDINET taxonomy so far. |
|
12-2 |
Versioning |
The
IFRS taxonomy uses the versioning solution as defined by the Versioning
Working Group. The versioning solution is not part of the official taxonomy
release but is additional information for each taxonomy release. The
versioning solution contains information about the differences between two
taxonomy releases enhanced with the versioning information about arts of
changes. Currently html change log is in use. |
We
are committed to using the specification when finalized. Currently, the
format is simple .csv change lists. |
Versioning
solution is really important for continuous taxonomy development. Thus, at
current stage, JFSA provide comments for Versioning specification which is
developed by XII. |
|
12-3 |
Rendering |
The
IFRS taxonomy addresses rendering of taxonomy structures (particularly
changes tables) with the use of two parallel presentation linkbases.
|
Not
mandated, but the Architecture document clearly indicates that the preferred
format for filings will eventually be Inline XBRL (called Mixed XBRL in the
document). The PG contains rules of thumb for making text blocks readable
using current generation SEC rendering tools. |
Proprietary
rendering technology is implemented in EDINET system. The concepts of this
technology are: - Contain required information for rendering such as
relationship among extended linkrole, context and
raw number into instance document based on Document Information Taxonomy
-Additional parameters such as raw label are set into the proprietary xml
file. |
At this time there are believed to be no domain related criteria with a high
impact on the architecture.
|
# |
Criterion |
IFRS |
US GAAP |
EDINET |
As noted earlier, expectations about the source and nature of taxonomy
extensions have a variety of impacts on the details of the taxonomy.
|
# |
Criterion |
IFRS |
US GAAP |
EDINET |
|
1-1-1 |
Rules
for taxonomy extensions |
Rules
stated in the IFRS Taxonomy Guide (Preparers Guide chapter). |
Yes
Stated in Preparers Guide |
There
are rules and guideline for corporate extension taxonomy development. These
rules and guidelines are benchmarked and were revised as a result of the
public comment phase and the 2nd pilot project. |
|
1-1-8 |
Creating
multiple financial document from single issuer at
the same time (e.g. series fund, guaranter...) |
Not
explicitly addressed. |
One
statement can contain as many funds as desired, each with its own member
along a series and class axis. |
Issuer
prepares instance document for each individual fund. |
|
2-1-1 |
FRTA
compliance |
FRTA
waivers are documented. Entities may use FRTA for quality checks but it is
not required. |
Five
waivers are documented, all of which have been reported as FRTA bugs. |
-Extension
taxonomy must be FRTA compliant with some exceptions -All 'AUTO' FRTA
validations are done by EDINET system right before submission. -Issuer gets
results of AUTO validations whether EDINET detects a FRTA violation or not |
|
2-2-2 |
Naming
convention |
id
my_entity_role-XXXXXX roleURI
http://www.my_entity.com/role/XXXXXX definition [XXXXXX] Name of the
statement or Notes | Dimension – Name of the note or name of the dimension |
PG
directs a naming convention in which the URI is derived from the taxonomy URI
and its description is of the form "000000 - Statement - Statement of
Income" |
These
are described in the "Framework Design Guide" |
|
2-4-2 |
Rules
for adding ELR |
Three
approaches (clean, reuse and mixed). |
No
restrictions. They are encouraged in the PG. |
There
are rules and guidelines are there: -adding new extended link role is
prohibited |
|
2-9-1 |
Rules
for including dimension in extended taxonomy |
New
dimensions may be added. |
PG
rules and rules of thumb guide you to use these appropriately. Typed members
shall not be used in extension taxonomies. |
n/a |
|
3-1-2 |
Rules
for instance documents |
IFRS
Taxonomy Guide (Preparers Guide chapter). |
PG
identifies a number of Rules. |
There
are rules and guidelines for instance document creation. These rules and
guidelines are benchmarked and have been revised as a result of the public
comment phase and the 2nd pilot project. |
|
3-2-1 |
FRIS
compliance (overview) |
Not
addressed. |
PG
rules have the effect of enforcing various FRIS rules |
-Instance
document must be FRIS compliant with some exceptions -All 'AUTO' FRIS
validations are done by EDINET system right before submission. -Issuer gets
results of AUTO validations weather EDINET detects a FRIS violation or not |
|
3-5-1 |
Precision/decimal
for different scales |
Rounded
to thousands -3 Rounded to millions -6 Rounded to two decimal places 2 Exact
numbers INF |
decimal="-6" for millions; decimal="-3" for
thousands, but the content of the element is of course the full number with
all necessary zeroes. |
Set
"decimal=-6" to describe "in millions" and
"decimal=-3" to describe "in thousands" |
|
3-6-5 |
Usage
of custom arcroles |
Not
used. |
Will
be used for disclosure of material and non material items |
http://info.edinet-fsa.go.jp/jp/fr/gaap/role/:
- NotesNumber - NumberPeriodStart
- NumberPeriodEnd |
|
3-7-1 |
Rules
for creating instance document with dimension |
According
to XDT. |
PG
guides users to extend using only minimal changes in preference to others.
There is a sequence of more invasive extensions including the selection of
domain members, addition of domain members, addition of axes, addition of
tables. |
n/a |
XBRL International Inc.. "XBRL
Dimensions 1.0"
Ignacio Hernández-Ros, and Hugh Wallis.
(See http://www.xbrl.org/Specification/XDT-REC-2006-09-18.htm)
XBRL International Inc..
"Financial Reporting Taxonomies Architecture 1.0 Recommendation dated
2005-04-25 with Corrected Errata 2006-03-20 "
Walter Hamscher, Mark Goodhand, Charles Hoffman, Brad
Homer, Josef Macdonald, Geoff Shuetrim, and Hugh
Wallis.
(See http://www.xbrl.org/technical/guidance/FRTA-RECOMMENDATION-2005-04-25+corrected-errata-2006-03-20.rtf)
XBRL International Inc..
"Extensible Business Reporting Language (XBRL) 2.1 Includes Corrected
Errata Up To 2008-07-02"
Phillip Engel, Walter Hamscher, Geoff Shuetrim, David
vun Kannon, and Hugh Wallis.
(See http://www.xbrl.org/Specification/XBRL-RECOMMENDATION-2003-12-31+Corrected-Errata-2008-07-02.htm)
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This document could not have been written without the contributions of many
people including the participants in the Taxonomy Architecture Working Group.
|
Date |
Author |
Details |
|
20
February 2009 |
Maciej
Piechocki |
Providing executive summary for the Taxonomy Comparison Framework as a first rough draft. |
|
23
February 2009 |
Maciej
Piechocki |
Adding explanation for capital market reporting context of the ITA and improving the wording. |
|
01
March 2009 |
Made specific reference to XBRL taxonomies rather than general taxonomies. Changed working group to Taxonomy Architecture working group. Added extracts of high impact areas. Grammar and style edits. |
|
|
14
March 2009 |
Change title, correct typos. |
|
|
18
March 2009 |
Makoto
Koizumi |
Change contributors. |
|
28
March 2009 |
Jim
Richards |
Grammatical changes and some formatting. |
|
20
April 2009 |
Maciej
Piechocki |
Adding link to the spreadsheet and changing status to PDWD. |
This appendix contains a list of the errata that have been incorporated into this document. This represents all those errata corrections that have been approved by the XBRL International Taxonomy Architecture Working Group up to and including 31 March 2009. Hyperlinks to relevant e-mail threads may only be followed by those who have access to the relevant mailing lists. Access to internal XBRL mailing lists is restricted to members of XBRL International Inc.
No errata have been incorporated into this document.