diff --git a/src/Illuminate/Database/Eloquent/Model.php b/src/Illuminate/Database/Eloquent/Model.php
index f446319d5d7a..52f1eb7aacdd 100755
--- a/src/Illuminate/Database/Eloquent/Model.php
+++ b/src/Illuminate/Database/Eloquent/Model.php
@@ -70,6 +70,13 @@ abstract class Model implements ArrayAccess, Arrayable, Jsonable, JsonSerializab
      */
     public $incrementing = true;
 
+    /**
+     * The type used by the incrementing ID.
+     *
+     * @var string
+     */
+    public $idType = 'int';
+
     /**
      * Indicates if the model should be timestamped.
      *
@@ -2763,7 +2770,7 @@ public function getCasts()
     {
         if ($this->getIncrementing()) {
             return array_merge([
-                $this->getKeyName() => 'int',
+                $this->getKeyName() => $this->idType,
             ], $this->casts);
         }
 
diff --git a/tests/Database/DatabaseEloquentModelTest.php b/tests/Database/DatabaseEloquentModelTest.php
index d6a19125f4ef..7ae315335399 100755
--- a/tests/Database/DatabaseEloquentModelTest.php
+++ b/tests/Database/DatabaseEloquentModelTest.php
@@ -1319,6 +1319,28 @@ public function testIssetBehavesCorrectlyWithAttributesAndRelationships()
         $this->assertTrue(isset($model->some_relation));
     }
 
+    public function testIntIdTypePreserved()
+    {
+        $model = $this->getMock('EloquentModelStub', ['newQueryWithoutScopes', 'updateTimestamps', 'refresh']);
+        $query = m::mock('Illuminate\Database\Eloquent\Builder');
+        $query->shouldReceive('insertGetId')->once()->with([], 'id')->andReturn(1);
+        $model->expects($this->once())->method('newQueryWithoutScopes')->will($this->returnValue($query));
+
+        $this->assertTrue($model->save());
+        $this->assertEquals(1, $model->id);
+    }
+
+    public function testStringIdTypePreserved()
+    {
+        $model = $this->getMock('EloquentIdTypeModelStub', ['newQueryWithoutScopes', 'updateTimestamps', 'refresh']);
+        $query = m::mock('Illuminate\Database\Eloquent\Builder');
+        $query->shouldReceive('insertGetId')->once()->with([], 'id')->andReturn('string id');
+        $model->expects($this->once())->method('newQueryWithoutScopes')->will($this->returnValue($query));
+
+        $this->assertTrue($model->save());
+        $this->assertEquals('string id', $model->id);
+    }
+
     protected function addMockConnection($model)
     {
         $model->setConnectionResolver($resolver = m::mock('Illuminate\Database\ConnectionResolverInterface'));
@@ -1431,6 +1453,11 @@ public function setIncrementing($value)
     }
 }
 
+class EloquentIdTypeModelStub extends EloquentModelStub
+{
+    public $idType = 'string';
+}
+
 class EloquentModelFindWithWritePdoStub extends Model
 {
     public function newQuery()