I couldn’t find how long the cookie expiry for a cookie based identity token is for ASP.net Identity anywhere in any documentation. I ended up decompiling Microsoft.Owin.Security.Cookies in which that property is defined. The default expiry is 14 days with a sliding expiration window.

The full set of defaults looks like:

UPDATE: *Pranav Rastogi *was kind enough to point out that the source code for this module is part of the Katana Project and is available on codeplex