This document provides an introduction to XBRL (eXtensible Business Reporting Language) and discusses potential assurance services accountants could provide related to XBRL. It explains that XBRL is a computer language used to tag financial data for improved reporting, but was not designed with information integrity in mind. Therefore, accountants could provide assurance that XBRL documents properly use tags and match original financial statements. The document outlines two types of reports an accountant could issue and the skills required, such as knowledge of regulations, IT, and XBRL software. It concludes that guidance and user sophistication around XBRL will continue developing.