Splitting a List of Entries Into Two Columns

{% for listItem in craft.entries.section('listItems').limit(null) %}
{% if loop.first %}
                <div class="column">
                    <ul class="plain">
{% endif %}
                        <li>{{ listItem.title }}</li>
{# Divide the list by 2 and get the floor() integer for comparison, using the // operator. -1 puts the odd item in the lefthand list. #}
{% if (loop.length // 2) == (loop.index - 1) %}
                    </ul>
                </div><!--
             --><div class="column">
                    <ul class="plain">
{% endif %}
{% if loop.last %}
                    </ul>
                </div>
{% endif %}
{% endfor %}