diff --git a/src/Relations/BelongsToManyCustom.php b/src/Relations/BelongsToManyCustom.php
index 2b9c0d1..a8cd2d6 100644
--- a/src/Relations/BelongsToManyCustom.php
+++ b/src/Relations/BelongsToManyCustom.php
@@ -35,7 +35,7 @@ public function attach($ids, array $attributes = [], $touch = true)
     public function detach($ids = null, $touch = true)
     {
         if (is_null($ids)) {
-            $ids = $this->query->pluck($this->query->qualifyColumn('id'))->toArray();
+            $ids = $this->query->pluck($this->query->qualifyColumn($this->relatedKey))->toArray();
         }
 
         list($idsOnly) = $this->getIdsWithAttributes($ids);