diff --git a/lib/ansible/modules/cloud/docker/docker.py b/lib/ansible/modules/cloud/docker/docker.py
index dfaa2973443..09f428140b7 100644
--- a/lib/ansible/modules/cloud/docker/docker.py
+++ b/lib/ansible/modules/cloud/docker/docker.py
@@ -169,8 +169,7 @@ options:
     description:
       - Username or UID to use within the container
     required: false
-    default:
-    aliases: []
+    default: null
     version_added: "2.0"
   username:
     description: