diff --git a/Source/cmDocumentVariables.cxx b/Source/cmDocumentVariables.cxx
index b42f2a95c..68d498330 100644
--- a/Source/cmDocumentVariables.cxx
+++ b/Source/cmDocumentVariables.cxx
@@ -200,6 +200,14 @@ void cmDocumentVariables::DefineVariables(cmake* cm)
      "build files.  (e.g. \"Unix Makefiles\", "
      "\"Visual Studio 6\", etc.)",false,
      "Variables that Provide Information");
+  cm->DefineProperty
+    ("CMAKE_EXTRA_GENERATOR", cmProperty::VARIABLE,
+     "The extra generator used to build the project.",
+     "When using the Eclipse, CodeBlocks or KDevelop generators, CMake "
+     "generates Makefiles (CMAKE_GENERATOR) and additionally project files "
+     "for the respective IDE. This IDE project file generator is stored in "
+     "CMAKE_EXTRA_GENERATOR (e.g. \"Eclipse CDT4\").",false,
+     "Variables that Provide Information");
   cm->DefineProperty
     ("CMAKE_HOME_DIRECTORY", cmProperty::VARIABLE,
      "Path to top of source tree.",