All publicly traded companies in the United States are required to file their financial statements with the SEC in iXBRL format. This means that these companies must tag their financial statements with the US GAAP Taxonomy.
Foreign private issuers (FPIs) that are listed on US stock exchanges are also required to file their financial statements with the SEC in iXBRL format. However, FPIs are not required to use the US GAAP Taxonomy. They can instead tag their financial statements with the IFRS Taxonomy or another XBRL taxonomy that is approved by the SEC.