Session ID

Hi im a newbbie , i need you help or advise , 

im making some report and i need to use the "id" from 

PHP Code:

$this->session->userdata('logged_in'); 


 i check 
$ses= $this->session->userdata('logged_in');
echo '<pre>';
print_r($ses);
and my data is 
[id] => 23
   [username] =>John Doe 

now how i can use this id because i do this and dont show anything 

$ses= $this->session->userdata('id');

echo '<pre>';
print_r($ses);
   

Your id is stored as an element in the $ses array so to access it you can use $ses['id']

no i want to use in my model so i try this 

PHP Code:

 function obtenerListaClientes()
    {
     
      $this->db->select('nombre_fantasia,direccion,fono, url');
      $this->db->from('clientes,users');
      $this->db->where('id_usuario = id AND id_usuario ='$ses);
      $clientes = $this->db->get();

      return $clientes->result(); 


in the controller i add 

$ses= $this->session->userdata('logged_in');

ofcourse no work i dont have any idea thx for the help