XBRL (eXtensible Business Reporting Language) is an open standard which supports information modeling and the expression of semantic meaning commonly required in business reporting. XBRL is XML-based. It uses the XML syntax and related XML technologies such as XML Schema, XLink, XPath, and Namespaces to articulate this semantic meaning. One use of XBRL is to define and exchange financial information, such as a financial statement. The XBRL Specification is developed and published by XBRL International, Inc. (XII).

XBRL is a standards-based way to communicate business and financial information. These communications are defined by metadata set out in taxonomies. Taxonomies capture the definition of individual reporting concepts as well as the relationships between concepts and other semantic meaning.

XBRLS is a simplified form of this standard intended to enable the non-XBRL expert to create both XBRL metadata and XBRL reports in a simple and convenient manner. At the same time, it seeks to improve the usability of XBRL, the interoperability among XBRL-based solutions and to reduce software development costs.

A wiki repository of XBRL projects can be found at Worldwide XBRL Projects, to be freely explored and updated.

Specification

The current (2008) version of XBRL is 2.1, with errata corrections. The normative version of all the XML Schemas is provided in the specification documents, not in separate files. A conformance suite is available to test processors of XBRL documents.

Document structure

In typical usage, XBRL consists of an instance document, containing primarily the business facts being reported, and a collection of taxonomies (called a Discoverable Taxonomy Set (DTS)), which define metadata about these facts, such as what the facts mean and how they relate to one another. XBRL uses XML Schema, XLink, and XPointer standards.

Instance document

The instance document begins with the root element. There may be more than one XBRL instance embedded in a larger XML document. The XBRL instance document itself holds the following information:

• Business Facts - facts can be divided into two categories
• Items are facts holding a single value. They are represented by a single XML element with the value as its content.
• Tuples are facts holding multiple values. They are represented by a single XML element containing nested Items or Tuples.

In the design of XBRL, all Item facts must be assigned a context.

• Contexts define the entity (e.g. company or individual) to which the fact applies, the period of time the fact is relevant, and an optional scenario. Date and time information appearing in the period element must conform to ISO 8601. Scenarios provide further contextual information about the facts, such as whether the business values reported are actual, projected, or budgeted.
• Units define the units used by numeric or fractional facts within the document, such as USD, shares. XBRL allows more complex units to be defined if necessary. Facts of a monetary nature must use a unit from the ISO 4217 namespace.
• Footnotes use XLink to associate one or more facts with some content.
• References to taxonomies, typically through schema references. It is also possible to link directly to a linkbase.