WordPress loads Jquery Automatically – is my idea correct to add it to the footer?

You shouldn’t enqueue jQuery by manually using wp_enqueue_script('jquery');. WordPress can enqueue it for you the right way. All you have to do is to declare jQuery as your script’s dependency:

wp_enqueue_script(
    'my-script', 
    get_template_directory_uri() .'/my-script.js', 
    array('jquery'), 
    null, 
    true
);

You can pass an array of dependencies as the 3rd parameter. Also, by setting the 5th parameter to true, you ask WordPress to enqueue this script in the footer.

If you really insist on moving jQuery to the footer, there are some optimization plugins such Autoptimize that can do this for you.

If you still really really would like a continuance, you can do so as follows:

function move_jquery_to_footer() {

    wp_deregister_script('jquery');
    wp_enqueue_script(
        'jquery', 
        'includes_url( '/js/jquery/jquery.js' )', 
        array(), 
        null, 
        true
   );

}
add_action('wp_enqueue_scripts', 'move_jquery_to_footer');

This is not recommended, and doing so can disqualify your theme or plugin in a lot of repositories and markets.

You can also defer parsing of your scripts. This way, your scripts will be parsed asynchronously. ( Code by @toscho from this answer )

add_filter( 'script_loader_tag', function ( $tag, $handle ) {

    return str_replace( ' src', ' defer="defer" src', $tag );

}, 10, 2 );