diff --git a/core/lib/Drupal/Core/Entity/EntityStorageBase.php b/core/lib/Drupal/Core/Entity/EntityStorageBase.php
index d32d8fbca684feb19360b65c96a97c5345897ece..85d7ef4359a0d6b1682514cffef0067c3ec03015 100644
--- a/core/lib/Drupal/Core/Entity/EntityStorageBase.php
+++ b/core/lib/Drupal/Core/Entity/EntityStorageBase.php
@@ -497,8 +497,8 @@ public function save(EntityInterface $entity) {
    * @param \Drupal\Core\Entity\EntityInterface $entity
    *   The saved entity.
    *
-   * @return int|string
-   *   The processed entity identifier.
+   * @return int|string|null
+   *   The processed entity identifier, or null for new entities.
    *
    * @throws \Drupal\Core\Entity\EntityStorageException
    *   If the entity identifier is invalid.