diff --git a/docs/root/configuration/observability/access_log/usage.rst b/docs/root/configuration/observability/access_log/usage.rst
index 09ad034f9622..30ea630e5b19 100644
--- a/docs/root/configuration/observability/access_log/usage.rst
+++ b/docs/root/configuration/observability/access_log/usage.rst
@@ -682,7 +682,11 @@ UDP
 .. _config_access_log_format_upstream_connection_id:
 
 %UPSTREAM_CONNECTION_ID%
-  An identifier for the upstream connection.
+  An identifier for the upstream connection. It can be used to
+  cross-reference TCP access logs across multiple log sinks, or to
+  cross-reference timer-based reports for the same connection. The identifier
+  is unique with high likelihood within an execution, but can duplicate across
+  multiple instances or between restarts.
 
 .. _config_access_log_format_stream_id: