I recently had a problem when I updated an app to Laravel 5.2. The view did not show my custom id correctly. I had to add the following to my model:
public $incrementing = false;
Now my custom id is showing correctly in the view.
Laravel Custom Primary Keys
Eloquent will also assume that each table has a primary key column named id. You may define a $primaryKey property to override this convention.
In addition, Eloquent assumes that the primary key is an incrementing integer value. If you wish to use a non-incrementing primary key, you must set the $incrementing property on your model to false.