diff --git a/core/modules/datetime/src/Plugin/Field/FieldType/DateRangeFieldItemList.php b/core/modules/datetime/src/Plugin/Field/FieldType/DateRangeFieldItemList.php
index fd4904b..1b02642 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldType/DateRangeFieldItemList.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldType/DateRangeFieldItemList.php
@@ -102,9 +102,9 @@ public static function processDefaultValue($default_value, FieldableEntityInterf
       // value fields.
       $default_value = [
         [
-          'start_value' => $value,
+          'value' => $value,
           'start_date' => $date,
-          'end_value' => $value,
+          'value2' => $value,
           'end_date' => $date,
         ],
       ];
diff --git a/core/modules/datetime/src/Plugin/Field/FieldType/DateRangeItem.php b/core/modules/datetime/src/Plugin/Field/FieldType/DateRangeItem.php
index 3e8aafa..f6e986b 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldType/DateRangeItem.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldType/DateRangeItem.php
@@ -45,7 +45,7 @@ public static function defaultStorageSettings() {
    * {@inheritdoc}
    */
   public static function propertyDefinitions(FieldStorageDefinitionInterface $field_definition) {
-    $properties['start_value'] = DataDefinition::create('datetime_iso8601')
+    $properties['value'] = DataDefinition::create('datetime_iso8601')
       ->setLabel(t('Start date value'))
       ->setRequired(TRUE);
 
@@ -54,9 +54,9 @@ public static function propertyDefinitions(FieldStorageDefinitionInterface $fiel
       ->setDescription(t('The computed start DateTime object.'))
       ->setComputed(TRUE)
       ->setClass('\Drupal\datetime\DateTimeComputed')
-      ->setSetting('date source', 'start_value');
+      ->setSetting('date source', 'value');
 
-    $properties['end_value'] = DataDefinition::create('datetime_iso8601')
+    $properties['value2'] = DataDefinition::create('datetime_iso8601')
       ->setLabel(t('End date value'))
       ->setRequired(TRUE);
 
@@ -65,7 +65,7 @@ public static function propertyDefinitions(FieldStorageDefinitionInterface $fiel
       ->setDescription(t('The computed end DateTime object.'))
       ->setComputed(TRUE)
       ->setClass('\Drupal\datetime\DateTimeComputed')
-      ->setSetting('date source', 'end_value');
+      ->setSetting('date source', 'value2');
 
     return $properties;
   }
@@ -76,20 +76,20 @@ public static function propertyDefinitions(FieldStorageDefinitionInterface $fiel
   public static function schema(FieldStorageDefinitionInterface $field_definition) {
     return [
       'columns' => [
-        'start_value' => [
+        'value' => [
           'description' => 'The start date value.',
           'type' => 'varchar',
           'length' => 20,
         ],
-        'end_value' => [
+        'value2' => [
           'description' => 'The end date value.',
           'type' => 'varchar',
           'length' => 20,
         ],
       ],
       'indexes' => [
-        'start_value' => ['start_value'],
-        'end_value' => ['end_value'],
+        'value' => ['value'],
+        'value2' => ['value2'],
       ],
     ];
   }
@@ -126,12 +126,12 @@ public static function generateSampleValue(FieldDefinitionInterface $field_defin
     $start = REQUEST_TIME - mt_rand(0, 86400 * 365) - 86400;
     $end = $start + 86400;
     if ($type == static::DATERANGE_TYPE_DATE) {
-      $values['start_value'] = gmdate(DATETIME_DATE_STORAGE_FORMAT, $start);
-      $values['end_value'] = gmdate(DATETIME_DATE_STORAGE_FORMAT, $end);
+      $values['value'] = gmdate(DATETIME_DATE_STORAGE_FORMAT, $start);
+      $values['value2'] = gmdate(DATETIME_DATE_STORAGE_FORMAT, $end);
     }
     else {
-      $values['start_value'] = gmdate(DATETIME_DATETIME_STORAGE_FORMAT, $start);
-      $values['end_value'] = gmdate(DATETIME_DATE_STORAGE_FORMAT, $end);
+      $values['value'] = gmdate(DATETIME_DATETIME_STORAGE_FORMAT, $start);
+      $values['value2'] = gmdate(DATETIME_DATE_STORAGE_FORMAT, $end);
     }
     return $values;
   }
@@ -140,8 +140,8 @@ public static function generateSampleValue(FieldDefinitionInterface $field_defin
    * {@inheritdoc}
    */
   public function isEmpty() {
-    $start_value = $this->get('start_value')->getValue();
-    $end_value = $this->get('end_value')->getValue();
+    $start_value = $this->get('value')->getValue();
+    $end_value = $this->get('value2')->getValue();
     return ($start_value === NULL || $start_value === '') && ($end_value === NULL || $end_value === '');
   }
 
@@ -150,10 +150,10 @@ public function isEmpty() {
    */
   public function onChange($property_name, $notify = TRUE) {
     // Enforce that the computed date is recalculated.
-    if ($property_name == 'start_value') {
+    if ($property_name == 'value') {
       $this->start_date = NULL;
     }
-    elseif ($property_name == 'end_value') {
+    elseif ($property_name == 'value2') {
       $this->end_date = NULL;
     }
     parent::onChange($property_name, $notify);
diff --git a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDatelistWidget.php b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDatelistWidget.php
index 4dea3e7..1693b61 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDatelistWidget.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDatelistWidget.php
@@ -75,17 +75,17 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
         break;
     }
 
-    $element['start_value'] = [
+    $element['value'] = [
       '#type' => 'datelist',
       '#date_increment' => $increment,
       '#date_part_order' => $date_part_order,
-    ] + $element['start_value'];
+    ] + $element['value'];
 
-    $element['end_value'] = [
+    $element['value2'] = [
       '#type' => 'datelist',
       '#date_increment' => $increment,
       '#date_part_order' => $date_part_order,
-    ] + $element['end_value'];
+    ] + $element['value2'];
 
     return $element;
   }
diff --git a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDefaultWidget.php b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDefaultWidget.php
index 20228a6..499833f 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDefaultWidget.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDefaultWidget.php
@@ -76,7 +76,7 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
         break;
     }
 
-    $element['start_value'] += array(
+    $element['value'] += array(
       '#date_date_format' => $date_format,
       '#date_date_element' => $date_type,
       '#date_date_callbacks' => array(),
@@ -85,7 +85,7 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
       '#date_time_callbacks' => array(),
     );
 
-    $element['end_value'] += array(
+    $element['value2'] += array(
       '#date_date_format' => $date_format,
       '#date_date_element' => $date_type,
       '#date_date_callbacks' => array(),
diff --git a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php
index ed535d1..8227dd8 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php
@@ -27,7 +27,7 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
     $element['#attributes']['class'][] = 'container-inline';
     $element['#element_validate'][] = [$this, 'validateStartEnd'];
 
-    $element['start_value'] = array(
+    $element['value'] = array(
       '#title' => $this->t('Start'),
       '#type' => 'datetime',
       '#default_value' => NULL,
@@ -36,7 +36,7 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
       '#required' => $element['#required'],
     );
 
-    $element['end_value'] = array(
+    $element['value2'] = array(
       '#title' => $this->t('End'),
       '#type' => 'datetime',
       '#default_value' => NULL,
@@ -55,8 +55,8 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
         // time.
         datetime_date_default_time($start_date);
       }
-      $start_date->setTimezone(new \DateTimeZone($element['start_value']['#date_timezone']));
-      $element['start_value']['#default_value'] = $start_date;
+      $start_date->setTimezone(new \DateTimeZone($element['value']['#date_timezone']));
+      $element['value']['#default_value'] = $start_date;
     }
 
     if ($items[$delta]->end_date) {
@@ -69,8 +69,8 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
         // time.
         datetime_date_default_time($end_date);
       }
-      $end_date->setTimezone(new \DateTimeZone($element['end_value']['#date_timezone']));
-      $element['end_value']['#default_value'] = $end_date;
+      $end_date->setTimezone(new \DateTimeZone($element['value2']['#date_timezone']));
+      $element['value2']['#default_value'] = $end_date;
     }
 
     return $element;
@@ -84,9 +84,9 @@ public function massageFormValues(array $values, array $form, FormStateInterface
     // DrupalDateTime object at this point. We need to convert it back to the
     // storage timezone and format.
     foreach ($values as &$item) {
-      if (!empty($item['start_value']) && $item['start_value'] instanceof DrupalDateTime) {
+      if (!empty($item['value']) && $item['value'] instanceof DrupalDateTime) {
         /** @var \Drupal\Core\Datetime\DrupalDateTime $start_date */
-        $start_date = $item['start_value'];
+        $start_date = $item['value'];
         switch ($this->getFieldSetting('daterange_type')) {
           case DateRangeItem::DATERANGE_TYPE_DATE:
             // If this is a date-only field, set it to the default time so the
@@ -101,12 +101,12 @@ public function massageFormValues(array $values, array $form, FormStateInterface
         }
         // Adjust the date for storage.
         $start_date->setTimezone(new \DateTimezone(DATETIME_STORAGE_TIMEZONE));
-        $item['start_value'] = $start_date->format($format);
+        $item['value'] = $start_date->format($format);
       }
 
-      if (!empty($item['end_value']) && $item['end_value'] instanceof DrupalDateTime) {
+      if (!empty($item['value2']) && $item['value2'] instanceof DrupalDateTime) {
         /** @var \Drupal\Core\Datetime\DrupalDateTime $end_date */
-        $end_date = $item['end_value'];
+        $end_date = $item['value2'];
         switch ($this->getFieldSetting('daterange_type')) {
           case DateRangeItem::DATERANGE_TYPE_DATE:
             // If this is a date-only field, set it to the default time so the
@@ -121,7 +121,7 @@ public function massageFormValues(array $values, array $form, FormStateInterface
         }
         // Adjust the date for storage.
         $end_date->setTimezone(new \DateTimezone(DATETIME_STORAGE_TIMEZONE));
-        $item['end_value'] = $end_date->format($format);
+        $item['value2'] = $end_date->format($format);
       }
     }
 
@@ -132,8 +132,8 @@ public function massageFormValues(array $values, array $form, FormStateInterface
    * Validates that the start <= the end date.
    */
   public function validateStartEnd($element, FormStateInterface $form_state) {
-    $start_date = $element['start_value']['#value']['object'];
-    $end_date = $element['end_value']['#value']['object'];
+    $start_date = $element['value']['#value']['object'];
+    $end_date = $element['value2']['#value']['object'];
 
     if ($start_date instanceof DrupalDateTime && $end_date instanceof DrupalDateTime) {
       /** @var \Drupal\Core\Datetime\DrupalDateTime $start_date */