How do I make an explicit path take precendence over a named parameter when defining angularjs routes

In the following example both routes resolve to the detail.html template. How do I make the first route take precedence since it's defined explicitly and not as a named parameter?

$routeProvider.
             when('/about', {templateUrl: 'about.html'}).
             when('/:id', {templateUrl: 'details.html'});