woocommerce订单产品信息未被退回

I am trying to get all woocommerce orders and find info about the products in each order. I have seen many examples on here and elsewhere on the web and they all seem to say to do the same thing but it isn't working. I am on Wordpress 4.1.1 and Woocommerce 2.3.3 here is my code:

$filters = array(
    'post_status' => 'any',
    'post_type' => 'shop_order',
    'posts_per_page' => 200,
    'paged' => 1,
    'orderby' =>'modified',
    'order' => 'ASC'
);

$loop = new WP_Query( $filters );

while ( $loop->have_posts() ) {
    $loop->the_post();
    $order = new WC_Order($loop->post->ID);

    foreach ($order->get_items() as $key => $lineItem) {
        print_r($lineItem);
    }
}

The problem is when I print_r($lineItem) there are only three properties only two of which are ever populated. A typical print_r($LineItem) looks like this:

Array ( 
    [name] => Fouta Towel – Pearl Grey & White Stripe 
    [type] => line_item 
    [item_meta] => 
)

How do I get the rest of the information about this order item, e.g the product id, whether it is a single / variable product etc