diff --git a/reference/configuration/framework.rst b/reference/configuration/framework.rst
index f6f11d7bd8f..f79160be10c 100644
--- a/reference/configuration/framework.rst
+++ b/reference/configuration/framework.rst
@@ -2847,9 +2847,14 @@ Can also be the service id of another cache pool where tags will be stored.
 default_lifetime
 """"""""""""""""
 
-**type**: ``integer``
+**type**: ``integer`` | ``string``
 
-Default lifetime of your cache items in seconds.
+Default lifetime of your cache items. Given an integer value to set the default
+lifetime in seconds. A string value could be ISO 8601 time interval, like ``"PT5M"``
+or a PHP date expression that is accepted by ``strtotime()``, like ``"5 minutes"``.
+
+If no value is provided, the cache adapter will fallback to the default value on
+the actual cache storage.
 
 provider
 """"""""