Today, Microsoft announced a new way to track all your Xbox game achievements you earned on Xbox One, Xbox 360, Windows and Windows Phone in once place. In the browser, you have to visit this URL to know the list of games and the achievements you have earned through them. The webpage looks like the above image.
— Larry Hryb (@majornelson) June 16, 2014
Visit https://account.xbox.com/en-US/Achievements/ for your details.