diff --git a/core/lib/Drupal/Core/Render/Element/Radio.php b/core/lib/Drupal/Core/Render/Element/Radio.php
index 643007b..826431f 100644
--- a/core/lib/Drupal/Core/Render/Element/Radio.php
+++ b/core/lib/Drupal/Core/Render/Element/Radio.php
@@ -42,15 +42,15 @@ public function getInfo() {
   * typed.
   *
   * @param mixed $value
-  *   A bool value which would be casted to string.
+  *   A value which would be casted.
   *
-  * @return string
-  *   The casted value of the bool value.
+  * @return mixed
+  *   The casted value of the parameter.
   */
   protected static function castValue($value)
   {
-    if (filter_var($value, FILTER_VALIDATE_BOOLEAN)) {
-       return (string) (int) $value;
+    if (is_bool($value) ||  (int) (bool) $value === (int) $value) {
+      return (string) (int) $value;
     }
     return $value;
   }