diff --git a/src/plugins/coreplugin/idocumentfactory.h b/src/plugins/coreplugin/idocumentfactory.h
index 44f1859bad6..a38176fa0ef 100644
--- a/src/plugins/coreplugin/idocumentfactory.h
+++ b/src/plugins/coreplugin/idocumentfactory.h
@@ -59,7 +59,6 @@ public:
     void addMimeType(const QString &mimeType) { m_mimeTypes.append(mimeType); }
 
 private:
-    Utils::Id m_id;
     Opener m_opener;
     QStringList m_mimeTypes;
     QString m_displayName;