The 'Z' is what adds the timezone info. As for output UTC, that seems to be the subject of some confusion -- people seem to gravitate toward moment.js.
Borrowing from this answer, you could do something like this without moment.js:
controller
var app1 = angular.module('app1',[]);
app1.controller('ctrl',['$scope',function($scope){
var toUTCDate = function(date){
var _utc = new Date(date.getUTCFullYear(), date.getUTCMonth(), date.getUTCDate(), date.getUTCHours(), date.getUTCMinutes(), date.getUTCSeconds());
return _utc;
};
var millisToUTCDate = function(millis){
return toUTCDate(new Date(millis));
};
$scope.toUTCDate = toUTCDate;
$scope.millisToUTCDate = millisToUTCDate;
}]);
template
<html ng-app="app1">
<head>
<script data-require="angular.js@*" data-semver="1.2.12" src="http://code.angularjs.org/1.2.12/angular.js"></script>
<link rel="stylesheet" href="style.css" />
<script src="script.js"></script>
</head>
<body>
<div ng-controller="ctrl">
<div>
utc {{millisToUTCDate(1400167800) | date:'dd-M-yyyy H:mm'}}
</div>
<div>
local {{1400167800 | date:'dd-M-yyyy H:mm'}}
</div>
</div>
</body>
</html>
here's plunker to play with it
See also this and this.
Also note that with this method, if you use the 'Z' from Angular's date filter, it seems it will still print your local timezone offset.