Hi florenz,
You can achieve it by using Session like below first assign the ID to the session and access it in all controller.
Refer below sample
//adding data to session
//assuming the method below will return ID(Guid)
var guid = Db.GetGuid(string userName);
//Store the Guid to a session
Session["Guid"] = guid;
//To get what you have stored to a session
int guid = Session["Guid"] as int;
//to clear the session value
Session["Guid"] = null;
And for more reference on Session in MVC you can refer below link
How to create and access session variables in ASP.NET MVC