Convert SELECT MAX() query with JOIN to CodeIgniter's query builder

This is my raw MySQL query:

SELECT MAX(A.BID),B.* 
FROM tbl_bid A 
INNER JOIN wl_customers B
    ON A.customers_id=B.customers_id
WHERE portfolio_id='$Id'

How can I write this as a query builder script in CodeIgniter?

Something like

$this->db->select('MAX(A.BID),B.*')
->join('wl_customers as B','A.customers_id=B.customers_id')
->where('portfolio_id',$Id)
->get('tbl_bid as A')
->row();