Как записать id дочерней категории

<?php $categories = get_categories(array('child_of' => 4, 'orderby' => 'id')); ?> 
<?php foreach ($categories as $child) { ?> 
 
<?php $categories = get_categories(array('child_of' => 14, 'orderby' => 'id', 'hide_empty' => 0)); ?> 
<?php foreach ($categories as $child) { ?> 
 
<?php } ?> 
 
 
<?php } ?>