diff --git a/app/code/Magento/Sales/Api/Data/CreditmemoInterface.php b/app/code/Magento/Sales/Api/Data/CreditmemoInterface.php
index 6b2548da10559eb525d95d78a410ee01c6d98a37..ecca646c69df93f4cf64cbb94b79856ddc8e19e1 100644
--- a/app/code/Magento/Sales/Api/Data/CreditmemoInterface.php
+++ b/app/code/Magento/Sales/Api/Data/CreditmemoInterface.php
@@ -304,7 +304,7 @@ interface CreditmemoInterface extends \Magento\Framework\Api\ExtensibleDataInter
     /**
      * Gets the credit memo base discount tax compensation amount.
      *
-     * @return float Credit memo base discount tax compensation amount.
+     * @return float|null Credit memo base discount tax compensation amount.
      */
     public function getBaseDiscountTaxCompensationAmount();
 
@@ -318,7 +318,7 @@ interface CreditmemoInterface extends \Magento\Framework\Api\ExtensibleDataInter
     /**
      * Gets the credit memo base shipping discount tax compensation amount.
      *
-     * @return float Credit memo base shipping discount tax compensation amount.
+     * @return float|null Credit memo base shipping discount tax compensation amount.
      */
     public function getBaseShippingDiscountTaxCompensationAmnt();
 
@@ -453,7 +453,7 @@ interface CreditmemoInterface extends \Magento\Framework\Api\ExtensibleDataInter
     /**
      * Gets the credit memo discount tax compensation amount.
      *
-     * @return float Credit memo discount tax compensation amount.
+     * @return float|null Credit memo discount tax compensation amount.
      */
     public function getDiscountTaxCompensationAmount();
 
@@ -501,7 +501,7 @@ interface CreditmemoInterface extends \Magento\Framework\Api\ExtensibleDataInter
     /**
      * Gets the credit memo shipping discount tax compensation amount.
      *
-     * @return float Credit memo shipping discount tax compensation amount.
+     * @return float|null Credit memo shipping discount tax compensation amount.
      */
     public function getShippingDiscountTaxCompensationAmount();
 
diff --git a/app/code/Magento/Sales/Api/Data/CreditmemoItemInterface.php b/app/code/Magento/Sales/Api/Data/CreditmemoItemInterface.php
index 20c5051ac493a0e72f074e4058c3b591e289ec85..8481a3426d0d8cff156a9966d7f2431ea58c85e8 100644
--- a/app/code/Magento/Sales/Api/Data/CreditmemoItemInterface.php
+++ b/app/code/Magento/Sales/Api/Data/CreditmemoItemInterface.php
@@ -169,14 +169,14 @@ interface CreditmemoItemInterface extends \Magento\Framework\Api\ExtensibleDataI
     /**
      * Gets the base discount amount for a credit memo item.
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountAmount();
 
     /**
      * Gets the base discount tax compensation amount for a credit memo item.
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationAmount();
 
@@ -275,7 +275,7 @@ interface CreditmemoItemInterface extends \Magento\Framework\Api\ExtensibleDataI
     /**
      * Gets the discount tax compensation amount for a credit memo item.
      *
-     * @return float Discount tax compensation amount.
+     * @return float|null Discount tax compensation amount.
      */
     public function getDiscountTaxCompensationAmount();
 
diff --git a/app/code/Magento/Sales/Api/Data/InvoiceInterface.php b/app/code/Magento/Sales/Api/Data/InvoiceInterface.php
index c2fc2937daddfccc5996970eb6737f444a78099d..77dfed277a262b3d6528125ce66da857f517621e 100644
--- a/app/code/Magento/Sales/Api/Data/InvoiceInterface.php
+++ b/app/code/Magento/Sales/Api/Data/InvoiceInterface.php
@@ -225,7 +225,7 @@ interface InvoiceInterface extends \Magento\Framework\Api\ExtensibleDataInterfac
     /**
      * Gets the base discount tax compensation amount for the invoice.
      *
-     * @return float Base discount tax compensation amount.
+     * @return float|null Base discount tax compensation amount.
      */
     public function getBaseDiscountTaxCompensationAmount();
 
@@ -239,7 +239,7 @@ interface InvoiceInterface extends \Magento\Framework\Api\ExtensibleDataInterfac
     /**
      * Gets the base shipping discount tax compensation amount for the invoice.
      *
-     * @return float Base shipping discount tax compensation amount.
+     * @return float|null Base shipping discount tax compensation amount.
      */
     public function getBaseShippingDiscountTaxCompensationAmnt();
 
@@ -381,7 +381,7 @@ interface InvoiceInterface extends \Magento\Framework\Api\ExtensibleDataInterfac
     /**
      * Gets the discount tax compensation amount for the invoice.
      *
-     * @return float Discount tax compensation amount.
+     * @return float|null Discount tax compensation amount.
      */
     public function getDiscountTaxCompensationAmount();
 
@@ -430,7 +430,7 @@ interface InvoiceInterface extends \Magento\Framework\Api\ExtensibleDataInterfac
     /**
      * Gets the shipping discount tax compensation amount for the invoice.
      *
-     * @return float Shipping discount tax compensation amount.
+     * @return float|null Shipping discount tax compensation amount.
      */
     public function getShippingDiscountTaxCompensationAmount();
 
diff --git a/app/code/Magento/Sales/Api/Data/InvoiceItemInterface.php b/app/code/Magento/Sales/Api/Data/InvoiceItemInterface.php
index 9e1addbdcae7bacd27ef57a40fd37a79921fed54..e76f644a8275faaae1658cd49c22329d3d69fb93 100644
--- a/app/code/Magento/Sales/Api/Data/InvoiceItemInterface.php
+++ b/app/code/Magento/Sales/Api/Data/InvoiceItemInterface.php
@@ -140,7 +140,7 @@ interface InvoiceItemInterface extends \Magento\Framework\Api\ExtensibleDataInte
     /**
      * Gets the base discount tax compensation amount for the invoice item.
      *
-     * @return float Base discount tax compensation amount.
+     * @return float|null Base discount tax compensation amount.
      */
     public function getBaseDiscountTaxCompensationAmount();
 
@@ -211,7 +211,7 @@ interface InvoiceItemInterface extends \Magento\Framework\Api\ExtensibleDataInte
     /**
      * Gets the discount tax compensation amount for the invoice item.
      *
-     * @return float Discount tax compensation amount.
+     * @return float|null Discount tax compensation amount.
      */
     public function getDiscountTaxCompensationAmount();
 
diff --git a/app/code/Magento/Sales/Api/Data/OrderInterface.php b/app/code/Magento/Sales/Api/Data/OrderInterface.php
index d494f869f1dffc69d454b8ce073b5a17d6a2b469..67152d152272c6638691526e335fb58498d386d9 100644
--- a/app/code/Magento/Sales/Api/Data/OrderInterface.php
+++ b/app/code/Magento/Sales/Api/Data/OrderInterface.php
@@ -643,21 +643,21 @@ interface OrderInterface extends \Magento\Framework\Api\ExtensibleDataInterface
     /**
      * Gets the base discount tax compensation amount for the order.
      *
-     * @return float Base discount tax compensation amount.
+     * @return float|null Base discount tax compensation amount.
      */
     public function getBaseDiscountTaxCompensationAmount();
 
     /**
      * Gets the base discount tax compensation invoiced amount for the order.
      *
-     * @return float Base discount tax compensation invoiced.
+     * @return float|null Base discount tax compensation invoiced.
      */
     public function getBaseDiscountTaxCompensationInvoiced();
 
     /**
      * Gets the base discount tax compensation refunded amount for the order.
      *
-     * @return float Base discount tax compensation refunded.
+     * @return float|null Base discount tax compensation refunded.
      */
     public function getBaseDiscountTaxCompensationRefunded();
 
@@ -685,7 +685,7 @@ interface OrderInterface extends \Magento\Framework\Api\ExtensibleDataInterface
     /**
      * Gets the base shipping discount tax compensation amount for the order.
      *
-     * @return float Base shipping discount tax compensation amount.
+     * @return float|null Base shipping discount tax compensation amount.
      */
     public function getBaseShippingDiscountTaxCompensationAmnt();
 
@@ -1107,21 +1107,21 @@ interface OrderInterface extends \Magento\Framework\Api\ExtensibleDataInterface
     /**
      * Gets the discount tax compensation amount for the order.
      *
-     * @return float Discount tax compensation amount.
+     * @return float|null Discount tax compensation amount.
      */
     public function getDiscountTaxCompensationAmount();
 
     /**
      * Gets the discount tax compensation invoiced amount for the order.
      *
-     * @return float Discount tax compensation invoiced amount.
+     * @return float|null Discount tax compensation invoiced amount.
      */
     public function getDiscountTaxCompensationInvoiced();
 
     /**
      * Gets the discount tax compensation refunded amount for the order.
      *
-     * @return float Discount tax compensation refunded amount.
+     * @return float|null Discount tax compensation refunded amount.
      */
     public function getDiscountTaxCompensationRefunded();
 
@@ -1268,7 +1268,7 @@ interface OrderInterface extends \Magento\Framework\Api\ExtensibleDataInterface
     /**
      * Gets the shipping discount tax compensation amount for the order.
      *
-     * @return float Shipping discount tax compensation amount.
+     * @return float|null Shipping discount tax compensation amount.
      */
     public function getShippingDiscountTaxCompensationAmount();
 
diff --git a/app/code/Magento/Sales/Api/Data/OrderItemInterface.php b/app/code/Magento/Sales/Api/Data/OrderItemInterface.php
index a9efe1f3b15be5d597f39fb45b99e3bd981aa495..298276b7e132a583017e1094515b7095d4d79555 100644
--- a/app/code/Magento/Sales/Api/Data/OrderItemInterface.php
+++ b/app/code/Magento/Sales/Api/Data/OrderItemInterface.php
@@ -457,21 +457,21 @@ interface OrderItemInterface extends \Magento\Framework\Api\ExtensibleDataInterf
     /**
      * Gets the base discount tax compensation amount for the order item.
      *
-     * @return float Base discount tax compensation amount.
+     * @return float|null Base discount tax compensation amount.
      */
     public function getBaseDiscountTaxCompensationAmount();
 
     /**
      * Gets the base discount tax compensation invoiced for the order item.
      *
-     * @return float Base discount tax compensation invoiced.
+     * @return float|null Base discount tax compensation invoiced.
      */
     public function getBaseDiscountTaxCompensationInvoiced();
 
     /**
      * Gets the base discount tax compensation refunded for the order item.
      *
-     * @return float Base discount tax compensation refunded.
+     * @return float|null Base discount tax compensation refunded.
      */
     public function getBaseDiscountTaxCompensationRefunded();
 
@@ -738,28 +738,28 @@ interface OrderItemInterface extends \Magento\Framework\Api\ExtensibleDataInterf
     /**
      * Gets the discount tax compensation amount for the order item.
      *
-     * @return float Discount tax compensation amount.
+     * @return float|null Discount tax compensation amount.
      */
     public function getDiscountTaxCompensationAmount();
 
     /**
      * Gets the discount tax compensation canceled for the order item.
      *
-     * @return float Discount tax compensation canceled.
+     * @return float|null Discount tax compensation canceled.
      */
     public function getDiscountTaxCompensationCanceled();
 
     /**
      * Gets the discount tax compensation invoiced for the order item.
      *
-     * @return float Discount tax compensation invoiced.
+     * @return float|null Discount tax compensation invoiced.
      */
     public function getDiscountTaxCompensationInvoiced();
 
     /**
      * Gets the discount tax compensation refunded for the order item.
      *
-     * @return float Discount tax compensation refunded.
+     * @return float|null Discount tax compensation refunded.
      */
     public function getDiscountTaxCompensationRefunded();
 
diff --git a/app/code/Magento/Sales/Api/Data/TotalInterface.php b/app/code/Magento/Sales/Api/Data/TotalInterface.php
index 1211b06fa3fedd0a227fb41b44b114ddf812ed85..e83720c7bb472c5e2d87343850b37b888432ebdc 100644
--- a/app/code/Magento/Sales/Api/Data/TotalInterface.php
+++ b/app/code/Magento/Sales/Api/Data/TotalInterface.php
@@ -114,7 +114,7 @@ interface TotalInterface extends ExtensibleDataInterface
     /**
      * Gets the base shipping discount tax compensation amount.
      *
-     * @return float Base shipping discount tax compensation amount.
+     * @return float|null Base shipping discount tax compensation amount.
      */
     public function getBaseShippingDiscountTaxCompensationAmnt();
 
@@ -177,7 +177,7 @@ interface TotalInterface extends ExtensibleDataInterface
     /**
      * Gets the shipping discount tax compensation amount.
      *
-     * @return float Shipping discount tax compensation amount.
+     * @return float|null Shipping discount tax compensation amount.
      */
     public function getShippingDiscountTaxCompensationAmount();
 
diff --git a/app/code/Magento/Sales/Model/Order.php b/app/code/Magento/Sales/Model/Order.php
index 8984d2312db36840282fecc7f4abc811357837e2..0cd80797d797d7e760c73087a2f14dcb0d408598 100644
--- a/app/code/Magento/Sales/Model/Order.php
+++ b/app/code/Magento/Sales/Model/Order.php
@@ -937,7 +937,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Retrieve order billing address
      *
-     * @return \Magento\Sales\Model\Order\Address|null
+     * @return \Magento\Sales\Api\Data\OrderAddressInterface|null
      */
     public function getBillingAddress()
     {
@@ -1640,7 +1640,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Retrieve order total due value
      *
-     * @return float
+     * @return float|null
      */
     public function getTotalDue()
     {
@@ -1652,7 +1652,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Retrieve order total due value
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTotalDue()
     {
@@ -1971,7 +1971,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     }
 
     /**
-     * @return \Magento\Sales\Api\Data\OrderStatusHistoryInterface[]
+     * @return \Magento\Sales\Api\Data\OrderStatusHistoryInterface[]|null
      */
     public function getStatusHistories()
     {
@@ -2009,7 +2009,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns adjustment_negative
      *
-     * @return float
+     * @return float|null
      */
     public function getAdjustmentNegative()
     {
@@ -2019,7 +2019,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns adjustment_positive
      *
-     * @return float
+     * @return float|null
      */
     public function getAdjustmentPositive()
     {
@@ -2029,7 +2029,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns applied_rule_ids
      *
-     * @return string
+     * @return string|null
      */
     public function getAppliedRuleIds()
     {
@@ -2039,7 +2039,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_adjustment_negative
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseAdjustmentNegative()
     {
@@ -2049,7 +2049,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_adjustment_positive
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseAdjustmentPositive()
     {
@@ -2059,7 +2059,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_currency_code
      *
-     * @return string
+     * @return string|null
      */
     public function getBaseCurrencyCode()
     {
@@ -2069,7 +2069,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountAmount()
     {
@@ -2079,7 +2079,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_discount_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountCanceled()
     {
@@ -2089,7 +2089,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_discount_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountInvoiced()
     {
@@ -2099,7 +2099,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_discount_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountRefunded()
     {
@@ -2119,7 +2119,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationAmount()
     {
@@ -2129,7 +2129,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_discount_tax_compensation_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationInvoiced()
     {
@@ -2139,7 +2139,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_discount_tax_compensation_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationRefunded()
     {
@@ -2149,7 +2149,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_shipping_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingAmount()
     {
@@ -2159,7 +2159,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_shipping_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingCanceled()
     {
@@ -2169,7 +2169,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_shipping_discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingDiscountAmount()
     {
@@ -2179,7 +2179,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_shipping_discount_tax_compensation_amnt
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingDiscountTaxCompensationAmnt()
     {
@@ -2189,7 +2189,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_shipping_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingInclTax()
     {
@@ -2199,7 +2199,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_shipping_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingInvoiced()
     {
@@ -2209,7 +2209,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_shipping_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingRefunded()
     {
@@ -2219,7 +2219,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_shipping_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingTaxAmount()
     {
@@ -2229,7 +2229,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_shipping_tax_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingTaxRefunded()
     {
@@ -2239,7 +2239,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_subtotal
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseSubtotal()
     {
@@ -2249,7 +2249,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_subtotal_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseSubtotalCanceled()
     {
@@ -2259,7 +2259,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_subtotal_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseSubtotalInclTax()
     {
@@ -2269,7 +2269,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_subtotal_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseSubtotalInvoiced()
     {
@@ -2279,7 +2279,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_subtotal_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseSubtotalRefunded()
     {
@@ -2289,7 +2289,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxAmount()
     {
@@ -2299,7 +2299,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_tax_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxCanceled()
     {
@@ -2309,7 +2309,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_tax_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxInvoiced()
     {
@@ -2319,7 +2319,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_tax_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxRefunded()
     {
@@ -2329,7 +2329,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_total_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTotalCanceled()
     {
@@ -2339,7 +2339,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_total_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTotalInvoiced()
     {
@@ -2349,7 +2349,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_total_invoiced_cost
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTotalInvoicedCost()
     {
@@ -2359,7 +2359,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_total_offline_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTotalOfflineRefunded()
     {
@@ -2369,7 +2369,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_total_online_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTotalOnlineRefunded()
     {
@@ -2379,7 +2379,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_total_paid
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTotalPaid()
     {
@@ -2389,7 +2389,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_total_qty_ordered
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTotalQtyOrdered()
     {
@@ -2399,7 +2399,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_total_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTotalRefunded()
     {
@@ -2409,7 +2409,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_to_global_rate
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseToGlobalRate()
     {
@@ -2419,7 +2419,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns base_to_order_rate
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseToOrderRate()
     {
@@ -2429,7 +2429,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns billing_address_id
      *
-     * @return int
+     * @return int|null
      */
     public function getBillingAddressId()
     {
@@ -2439,7 +2439,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns can_ship_partially
      *
-     * @return int
+     * @return int|null
      */
     public function getCanShipPartially()
     {
@@ -2449,7 +2449,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns can_ship_partially_item
      *
-     * @return int
+     * @return int|null
      */
     public function getCanShipPartiallyItem()
     {
@@ -2459,7 +2459,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns coupon_code
      *
-     * @return string
+     * @return string|null
      */
     public function getCouponCode()
     {
@@ -2469,7 +2469,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns created_at
      *
-     * @return string
+     * @return string|null
      */
     public function getCreatedAt()
     {
@@ -2487,7 +2487,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_dob
      *
-     * @return string
+     * @return string|null
      */
     public function getCustomerDob()
     {
@@ -2507,7 +2507,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_firstname
      *
-     * @return string
+     * @return string|null
      */
     public function getCustomerFirstname()
     {
@@ -2517,7 +2517,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_gender
      *
-     * @return int
+     * @return int|null
      */
     public function getCustomerGender()
     {
@@ -2527,7 +2527,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_group_id
      *
-     * @return int
+     * @return int|null
      */
     public function getCustomerGroupId()
     {
@@ -2537,7 +2537,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_id
      *
-     * @return int
+     * @return int|null
      */
     public function getCustomerId()
     {
@@ -2547,7 +2547,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_is_guest
      *
-     * @return int
+     * @return int|null
      */
     public function getCustomerIsGuest()
     {
@@ -2557,7 +2557,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_lastname
      *
-     * @return string
+     * @return string|null
      */
     public function getCustomerLastname()
     {
@@ -2567,7 +2567,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_middlename
      *
-     * @return string
+     * @return string|null
      */
     public function getCustomerMiddlename()
     {
@@ -2577,7 +2577,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_note
      *
-     * @return string
+     * @return string|null
      */
     public function getCustomerNote()
     {
@@ -2587,7 +2587,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_note_notify
      *
-     * @return int
+     * @return int|null
      */
     public function getCustomerNoteNotify()
     {
@@ -2597,7 +2597,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_prefix
      *
-     * @return string
+     * @return string|null
      */
     public function getCustomerPrefix()
     {
@@ -2607,7 +2607,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_suffix
      *
-     * @return string
+     * @return string|null
      */
     public function getCustomerSuffix()
     {
@@ -2617,7 +2617,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns customer_taxvat
      *
-     * @return string
+     * @return string|null
      */
     public function getCustomerTaxvat()
     {
@@ -2627,7 +2627,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountAmount()
     {
@@ -2637,7 +2637,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns discount_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountCanceled()
     {
@@ -2647,7 +2647,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns discount_description
      *
-     * @return string
+     * @return string|null
      */
     public function getDiscountDescription()
     {
@@ -2657,7 +2657,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns discount_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountInvoiced()
     {
@@ -2667,7 +2667,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns discount_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountRefunded()
     {
@@ -2677,7 +2677,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns edit_increment
      *
-     * @return int
+     * @return int|null
      */
     public function getEditIncrement()
     {
@@ -2687,7 +2687,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns email_sent
      *
-     * @return int
+     * @return int|null
      */
     public function getEmailSent()
     {
@@ -2697,7 +2697,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns ext_customer_id
      *
-     * @return string
+     * @return string|null
      */
     public function getExtCustomerId()
     {
@@ -2707,7 +2707,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns ext_order_id
      *
-     * @return string
+     * @return string|null
      */
     public function getExtOrderId()
     {
@@ -2717,7 +2717,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns forced_shipment_with_invoice
      *
-     * @return int
+     * @return int|null
      */
     public function getForcedShipmentWithInvoice()
     {
@@ -2727,7 +2727,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns global_currency_code
      *
-     * @return string
+     * @return string|null
      */
     public function getGlobalCurrencyCode()
     {
@@ -2747,7 +2747,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationAmount()
     {
@@ -2757,7 +2757,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns discount_tax_compensation_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationInvoiced()
     {
@@ -2767,7 +2767,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns discount_tax_compensation_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationRefunded()
     {
@@ -2777,7 +2777,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns hold_before_state
      *
-     * @return string
+     * @return string|null
      */
     public function getHoldBeforeState()
     {
@@ -2787,7 +2787,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns hold_before_status
      *
-     * @return string
+     * @return string|null
      */
     public function getHoldBeforeStatus()
     {
@@ -2797,7 +2797,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns is_virtual
      *
-     * @return int
+     * @return int|null
      */
     public function getIsVirtual()
     {
@@ -2807,7 +2807,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns order_currency_code
      *
-     * @return string
+     * @return string|null
      */
     public function getOrderCurrencyCode()
     {
@@ -2817,7 +2817,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns original_increment_id
      *
-     * @return string
+     * @return string|null
      */
     public function getOriginalIncrementId()
     {
@@ -2827,7 +2827,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns payment_authorization_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getPaymentAuthorizationAmount()
     {
@@ -2837,7 +2837,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns payment_auth_expiration
      *
-     * @return int
+     * @return int|null
      */
     public function getPaymentAuthExpiration()
     {
@@ -2847,7 +2847,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns protect_code
      *
-     * @return string
+     * @return string|null
      */
     public function getProtectCode()
     {
@@ -2857,7 +2857,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns quote_address_id
      *
-     * @return int
+     * @return int|null
      */
     public function getQuoteAddressId()
     {
@@ -2867,7 +2867,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns quote_id
      *
-     * @return int
+     * @return int|null
      */
     public function getQuoteId()
     {
@@ -2877,7 +2877,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns relation_child_id
      *
-     * @return string
+     * @return string|null
      */
     public function getRelationChildId()
     {
@@ -2887,7 +2887,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns relation_child_real_id
      *
-     * @return string
+     * @return string|null
      */
     public function getRelationChildRealId()
     {
@@ -2897,7 +2897,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns relation_parent_id
      *
-     * @return string
+     * @return string|null
      */
     public function getRelationParentId()
     {
@@ -2907,7 +2907,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns relation_parent_real_id
      *
-     * @return string
+     * @return string|null
      */
     public function getRelationParentRealId()
     {
@@ -2917,7 +2917,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns remote_ip
      *
-     * @return string
+     * @return string|null
      */
     public function getRemoteIp()
     {
@@ -2927,7 +2927,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns shipping_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingAmount()
     {
@@ -2937,7 +2937,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns shipping_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingCanceled()
     {
@@ -2947,7 +2947,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns shipping_description
      *
-     * @return string
+     * @return string|null
      */
     public function getShippingDescription()
     {
@@ -2957,7 +2957,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns shipping_discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingDiscountAmount()
     {
@@ -2967,7 +2967,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns shipping_discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingDiscountTaxCompensationAmount()
     {
@@ -2977,7 +2977,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns shipping_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingInclTax()
     {
@@ -2987,7 +2987,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns shipping_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingInvoiced()
     {
@@ -2997,7 +2997,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns shipping_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingRefunded()
     {
@@ -3007,7 +3007,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns shipping_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingTaxAmount()
     {
@@ -3017,7 +3017,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns shipping_tax_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingTaxRefunded()
     {
@@ -3027,7 +3027,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns state
      *
-     * @return string
+     * @return string|null
      */
     public function getState()
     {
@@ -3037,7 +3037,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns status
      *
-     * @return string
+     * @return string|null
      */
     public function getStatus()
     {
@@ -3047,7 +3047,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns store_currency_code
      *
-     * @return string
+     * @return string|null
      */
     public function getStoreCurrencyCode()
     {
@@ -3057,7 +3057,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns store_id
      *
-     * @return int
+     * @return int|null
      */
     public function getStoreId()
     {
@@ -3067,7 +3067,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns store_name
      *
-     * @return string
+     * @return string|null
      */
     public function getStoreName()
     {
@@ -3077,7 +3077,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns store_to_base_rate
      *
-     * @return float
+     * @return float|null
      */
     public function getStoreToBaseRate()
     {
@@ -3087,7 +3087,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns store_to_order_rate
      *
-     * @return float
+     * @return float|null
      */
     public function getStoreToOrderRate()
     {
@@ -3097,7 +3097,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns subtotal
      *
-     * @return float
+     * @return float|null
      */
     public function getSubtotal()
     {
@@ -3107,7 +3107,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns subtotal_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getSubtotalCanceled()
     {
@@ -3117,7 +3117,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns subtotal_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getSubtotalInclTax()
     {
@@ -3127,7 +3127,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns subtotal_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getSubtotalInvoiced()
     {
@@ -3137,7 +3137,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns subtotal_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getSubtotalRefunded()
     {
@@ -3147,7 +3147,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxAmount()
     {
@@ -3157,7 +3157,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns tax_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxCanceled()
     {
@@ -3167,7 +3167,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns tax_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxInvoiced()
     {
@@ -3177,7 +3177,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns tax_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxRefunded()
     {
@@ -3187,7 +3187,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns total_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getTotalCanceled()
     {
@@ -3197,7 +3197,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns total_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getTotalInvoiced()
     {
@@ -3207,7 +3207,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns total_item_count
      *
-     * @return int
+     * @return int|null
      */
     public function getTotalItemCount()
     {
@@ -3217,7 +3217,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns total_offline_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getTotalOfflineRefunded()
     {
@@ -3227,7 +3227,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns total_online_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getTotalOnlineRefunded()
     {
@@ -3237,7 +3237,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns total_paid
      *
-     * @return float
+     * @return float|null
      */
     public function getTotalPaid()
     {
@@ -3247,7 +3247,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns total_qty_ordered
      *
-     * @return float
+     * @return float|null
      */
     public function getTotalQtyOrdered()
     {
@@ -3257,7 +3257,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns total_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getTotalRefunded()
     {
@@ -3267,7 +3267,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns updated_at
      *
-     * @return string
+     * @return string|null
      */
     public function getUpdatedAt()
     {
@@ -3277,7 +3277,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns weight
      *
-     * @return float
+     * @return float|null
      */
     public function getWeight()
     {
@@ -3287,7 +3287,7 @@ class Order extends AbstractModel implements EntityInterface, OrderInterface
     /**
      * Returns x_forwarded_for
      *
-     * @return string
+     * @return string|null
      */
     public function getXForwardedFor()
     {
diff --git a/app/code/Magento/Sales/Model/Order/Creditmemo.php b/app/code/Magento/Sales/Model/Order/Creditmemo.php
index 34aedc3d5d70539036ea67f2f1d3e96fa1f6cb02..b40b09a4883d4a0cd331d1b573a9e5107f0358d9 100644
--- a/app/code/Magento/Sales/Model/Order/Creditmemo.php
+++ b/app/code/Magento/Sales/Model/Order/Creditmemo.php
@@ -9,7 +9,6 @@
 namespace Magento\Sales\Model\Order;
 
 use Magento\Framework\Api\AttributeValueFactory;
-use Magento\Framework\Exception\LocalizedException;
 use Magento\Framework\Pricing\PriceCurrencyInterface;
 use Magento\Sales\Api\Data\CreditmemoInterface;
 use Magento\Sales\Model\AbstractModel;
@@ -787,7 +786,7 @@ class Creditmemo extends AbstractModel implements EntityInterface, CreditmemoInt
     /**
      * Returns base_discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationAmount()
     {
@@ -807,7 +806,7 @@ class Creditmemo extends AbstractModel implements EntityInterface, CreditmemoInt
     /**
      * Returns base_shipping_discount_tax_compensation_amnt
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingDiscountTaxCompensationAmnt()
     {
@@ -965,7 +964,7 @@ class Creditmemo extends AbstractModel implements EntityInterface, CreditmemoInt
     /**
      * Returns discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationAmount()
     {
@@ -1025,7 +1024,7 @@ class Creditmemo extends AbstractModel implements EntityInterface, CreditmemoInt
     /**
      * Returns shipping_discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingDiscountTaxCompensationAmount()
     {
diff --git a/app/code/Magento/Sales/Model/Order/Creditmemo/Item.php b/app/code/Magento/Sales/Model/Order/Creditmemo/Item.php
index 4489655e36af94b84d79b862a77bc176f9c6b8ad..1ca534939f0caf4c989a098a72dae197ff4b4fa0 100644
--- a/app/code/Magento/Sales/Model/Order/Creditmemo/Item.php
+++ b/app/code/Magento/Sales/Model/Order/Creditmemo/Item.php
@@ -288,7 +288,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns additional_data
      *
-     * @return string
+     * @return string|null
      */
     public function getAdditionalData()
     {
@@ -308,7 +308,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns base_discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountAmount()
     {
@@ -318,7 +318,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns base_discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationAmount()
     {
@@ -338,7 +338,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns base_price_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getBasePriceInclTax()
     {
@@ -348,7 +348,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns base_row_total
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseRowTotal()
     {
@@ -358,7 +358,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns base_row_total_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseRowTotalInclTax()
     {
@@ -368,7 +368,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns base_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxAmount()
     {
@@ -378,7 +378,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns base_weee_tax_applied_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseWeeeTaxAppliedAmount()
     {
@@ -388,7 +388,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns base_weee_tax_applied_row_amnt
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseWeeeTaxAppliedRowAmnt()
     {
@@ -398,7 +398,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns base_weee_tax_disposition
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseWeeeTaxDisposition()
     {
@@ -408,7 +408,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns base_weee_tax_row_disposition
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseWeeeTaxRowDisposition()
     {
@@ -418,7 +418,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns description
      *
-     * @return string
+     * @return string|null
      */
     public function getDescription()
     {
@@ -428,7 +428,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountAmount()
     {
@@ -438,7 +438,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationAmount()
     {
@@ -448,7 +448,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns name
      *
-     * @return string
+     * @return string|null
      */
     public function getName()
     {
@@ -468,7 +468,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns parent_id
      *
-     * @return int
+     * @return int|null
      */
     public function getParentId()
     {
@@ -478,7 +478,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns price
      *
-     * @return float
+     * @return float|null
      */
     public function getPrice()
     {
@@ -488,7 +488,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns price_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getPriceInclTax()
     {
@@ -498,7 +498,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns product_id
      *
-     * @return int
+     * @return int|null
      */
     public function getProductId()
     {
@@ -518,7 +518,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns row_total
      *
-     * @return float
+     * @return float|null
      */
     public function getRowTotal()
     {
@@ -528,7 +528,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns row_total_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getRowTotalInclTax()
     {
@@ -538,7 +538,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns sku
      *
-     * @return string
+     * @return string|null
      */
     public function getSku()
     {
@@ -548,7 +548,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxAmount()
     {
@@ -558,7 +558,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns weee_tax_applied
      *
-     * @return string
+     * @return string|null
      */
     public function getWeeeTaxApplied()
     {
@@ -568,7 +568,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns weee_tax_applied_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getWeeeTaxAppliedAmount()
     {
@@ -578,7 +578,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns weee_tax_applied_row_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getWeeeTaxAppliedRowAmount()
     {
@@ -588,7 +588,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns weee_tax_disposition
      *
-     * @return float
+     * @return float|null
      */
     public function getWeeeTaxDisposition()
     {
@@ -598,7 +598,7 @@ class Item extends AbstractModel implements CreditmemoItemInterface
     /**
      * Returns weee_tax_row_disposition
      *
-     * @return float
+     * @return float|null
      */
     public function getWeeeTaxRowDisposition()
     {
diff --git a/app/code/Magento/Sales/Model/Order/Invoice.php b/app/code/Magento/Sales/Model/Order/Invoice.php
index 3df33c0780a27cff788d50c608510861df6716f0..a977de41c558540e50e419e19c0c7fa02e8d7a33 100644
--- a/app/code/Magento/Sales/Model/Order/Invoice.php
+++ b/app/code/Magento/Sales/Model/Order/Invoice.php
@@ -777,7 +777,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Return invoice comments
      *
-     * @return \Magento\Sales\Api\Data\InvoiceCommentInterface[]
+     * @return \Magento\Sales\Api\Data\InvoiceCommentInterface[]|null
      */
     public function getComments()
     {
@@ -805,7 +805,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_total_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTotalRefunded()
     {
@@ -815,7 +815,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns discount_description
      *
-     * @return string
+     * @return string|null
      */
     public function getDiscountDescription()
     {
@@ -833,7 +833,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_currency_code
      *
-     * @return string
+     * @return string|null
      */
     public function getBaseCurrencyCode()
     {
@@ -843,7 +843,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountAmount()
     {
@@ -853,7 +853,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_grand_total
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseGrandTotal()
     {
@@ -863,7 +863,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationAmount()
     {
@@ -873,7 +873,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_shipping_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingAmount()
     {
@@ -883,7 +883,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_shipping_discount_tax_compensation_amnt
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingDiscountTaxCompensationAmnt()
     {
@@ -893,7 +893,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_shipping_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingInclTax()
     {
@@ -903,7 +903,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_shipping_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseShippingTaxAmount()
     {
@@ -913,7 +913,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_subtotal
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseSubtotal()
     {
@@ -923,7 +923,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_subtotal_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseSubtotalInclTax()
     {
@@ -933,7 +933,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxAmount()
     {
@@ -943,7 +943,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_to_global_rate
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseToGlobalRate()
     {
@@ -953,7 +953,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns base_to_order_rate
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseToOrderRate()
     {
@@ -963,7 +963,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns billing_address_id
      *
-     * @return int
+     * @return int|null
      */
     public function getBillingAddressId()
     {
@@ -973,7 +973,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns can_void_flag
      *
-     * @return int
+     * @return int|null
      */
     public function getCanVoidFlag()
     {
@@ -983,7 +983,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns created_at
      *
-     * @return string
+     * @return string|null
      */
     public function getCreatedAt()
     {
@@ -1001,7 +1001,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountAmount()
     {
@@ -1011,7 +1011,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns email_sent
      *
-     * @return int
+     * @return int|null
      */
     public function getEmailSent()
     {
@@ -1021,7 +1021,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns global_currency_code
      *
-     * @return string
+     * @return string|null
      */
     public function getGlobalCurrencyCode()
     {
@@ -1031,7 +1031,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns grand_total
      *
-     * @return float
+     * @return float|null
      */
     public function getGrandTotal()
     {
@@ -1041,7 +1041,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationAmount()
     {
@@ -1051,7 +1051,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns is_used_for_refund
      *
-     * @return int
+     * @return int|null
      */
     public function getIsUsedForRefund()
     {
@@ -1061,7 +1061,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns order_currency_code
      *
-     * @return string
+     * @return string|null
      */
     public function getOrderCurrencyCode()
     {
@@ -1081,7 +1081,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns shipping_address_id
      *
-     * @return int
+     * @return int|null
      */
     public function getShippingAddressId()
     {
@@ -1091,7 +1091,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns shipping_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingAmount()
     {
@@ -1101,7 +1101,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns shipping_discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingDiscountTaxCompensationAmount()
     {
@@ -1111,7 +1111,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns shipping_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingInclTax()
     {
@@ -1121,7 +1121,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns shipping_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getShippingTaxAmount()
     {
@@ -1131,7 +1131,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns state
      *
-     * @return int
+     * @return int|null
      */
     public function getState()
     {
@@ -1141,7 +1141,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns store_currency_code
      *
-     * @return string
+     * @return string|null
      */
     public function getStoreCurrencyCode()
     {
@@ -1151,7 +1151,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns store_id
      *
-     * @return int
+     * @return int|null
      */
     public function getStoreId()
     {
@@ -1161,7 +1161,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns store_to_base_rate
      *
-     * @return float
+     * @return float|null
      */
     public function getStoreToBaseRate()
     {
@@ -1171,7 +1171,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns store_to_order_rate
      *
-     * @return float
+     * @return float|null
      */
     public function getStoreToOrderRate()
     {
@@ -1181,7 +1181,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns subtotal
      *
-     * @return float
+     * @return float|null
      */
     public function getSubtotal()
     {
@@ -1191,7 +1191,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns subtotal_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getSubtotalInclTax()
     {
@@ -1201,7 +1201,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxAmount()
     {
@@ -1221,7 +1221,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns transaction_id
      *
-     * @return string
+     * @return string|null
      */
     public function getTransactionId()
     {
@@ -1242,7 +1242,7 @@ class Invoice extends AbstractModel implements EntityInterface, InvoiceInterface
     /**
      * Returns updated_at
      *
-     * @return string
+     * @return string|null
      */
     public function getUpdatedAt()
     {
diff --git a/app/code/Magento/Sales/Model/Order/Invoice/Item.php b/app/code/Magento/Sales/Model/Order/Invoice/Item.php
index 2e8b66e891e82c9e240b876957aedc9abf363f60..8f0add409086e936962a24c04b31f842b6edef6f 100644
--- a/app/code/Magento/Sales/Model/Order/Invoice/Item.php
+++ b/app/code/Magento/Sales/Model/Order/Invoice/Item.php
@@ -269,7 +269,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns additional_data
      *
-     * @return string
+     * @return string|null
      */
     public function getAdditionalData()
     {
@@ -279,7 +279,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns base_cost
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseCost()
     {
@@ -289,7 +289,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns base_discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountAmount()
     {
@@ -299,7 +299,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns base_discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationAmount()
     {
@@ -309,7 +309,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns base_price
      *
-     * @return float
+     * @return float|null
      */
     public function getBasePrice()
     {
@@ -319,7 +319,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns base_price_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getBasePriceInclTax()
     {
@@ -329,7 +329,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns base_row_total
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseRowTotal()
     {
@@ -339,7 +339,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns base_row_total_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseRowTotalInclTax()
     {
@@ -349,7 +349,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns base_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxAmount()
     {
@@ -359,7 +359,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns description
      *
-     * @return string
+     * @return string|null
      */
     public function getDescription()
     {
@@ -369,7 +369,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountAmount()
     {
@@ -379,7 +379,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationAmount()
     {
@@ -389,7 +389,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns name
      *
-     * @return string
+     * @return string|null
      */
     public function getName()
     {
@@ -409,7 +409,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns parent_id
      *
-     * @return int
+     * @return int|null
      */
     public function getParentId()
     {
@@ -419,7 +419,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns price
      *
-     * @return float
+     * @return float|null
      */
     public function getPrice()
     {
@@ -429,7 +429,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns price_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getPriceInclTax()
     {
@@ -439,7 +439,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns product_id
      *
-     * @return int
+     * @return int|null
      */
     public function getProductId()
     {
@@ -459,7 +459,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns row_total
      *
-     * @return float
+     * @return float|null
      */
     public function getRowTotal()
     {
@@ -469,7 +469,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns row_total_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getRowTotalInclTax()
     {
@@ -489,7 +489,7 @@ class Item extends AbstractModel implements InvoiceItemInterface
     /**
      * Returns tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxAmount()
     {
diff --git a/app/code/Magento/Sales/Model/Order/Item.php b/app/code/Magento/Sales/Model/Order/Item.php
index 911d279f3bca9af443323cbe02b4e52fce21ed31..7aaa0297472ec15676906ab4afc200bef885c9ce 100644
--- a/app/code/Magento/Sales/Model/Order/Item.php
+++ b/app/code/Magento/Sales/Model/Order/Item.php
@@ -435,7 +435,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Redeclare getter for back compatibility
      *
-     * @return float
+     * @return float|null
      */
     public function getOriginalPrice()
     {
@@ -692,7 +692,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns additional_data
      *
-     * @return string
+     * @return string|null
      */
     public function getAdditionalData()
     {
@@ -702,7 +702,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns amount_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getAmountRefunded()
     {
@@ -712,7 +712,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns applied_rule_ids
      *
-     * @return string
+     * @return string|null
      */
     public function getAppliedRuleIds()
     {
@@ -722,7 +722,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_amount_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseAmountRefunded()
     {
@@ -732,7 +732,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_cost
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseCost()
     {
@@ -742,7 +742,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountAmount()
     {
@@ -752,7 +752,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_discount_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountInvoiced()
     {
@@ -762,7 +762,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_discount_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountRefunded()
     {
@@ -772,7 +772,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationAmount()
     {
@@ -782,7 +782,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_discount_tax_compensation_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationInvoiced()
     {
@@ -792,7 +792,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_discount_tax_compensation_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseDiscountTaxCompensationRefunded()
     {
@@ -802,7 +802,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_original_price
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseOriginalPrice()
     {
@@ -812,7 +812,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_price
      *
-     * @return float
+     * @return float|null
      */
     public function getBasePrice()
     {
@@ -822,7 +822,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_price_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getBasePriceInclTax()
     {
@@ -832,7 +832,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_row_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseRowInvoiced()
     {
@@ -842,7 +842,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_row_total
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseRowTotal()
     {
@@ -852,7 +852,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_row_total_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseRowTotalInclTax()
     {
@@ -862,7 +862,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxAmount()
     {
@@ -872,7 +872,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_tax_before_discount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxBeforeDiscount()
     {
@@ -882,7 +882,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_tax_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxInvoiced()
     {
@@ -892,7 +892,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_tax_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseTaxRefunded()
     {
@@ -902,7 +902,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_weee_tax_applied_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseWeeeTaxAppliedAmount()
     {
@@ -912,7 +912,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_weee_tax_applied_row_amnt
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseWeeeTaxAppliedRowAmnt()
     {
@@ -922,7 +922,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_weee_tax_disposition
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseWeeeTaxDisposition()
     {
@@ -932,7 +932,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns base_weee_tax_row_disposition
      *
-     * @return float
+     * @return float|null
      */
     public function getBaseWeeeTaxRowDisposition()
     {
@@ -942,7 +942,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns created_at
      *
-     * @return string
+     * @return string|null
      */
     public function getCreatedAt()
     {
@@ -960,7 +960,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns description
      *
-     * @return string
+     * @return string|null
      */
     public function getDescription()
     {
@@ -970,7 +970,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns discount_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountAmount()
     {
@@ -980,7 +980,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns discount_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountInvoiced()
     {
@@ -990,7 +990,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns discount_percent
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountPercent()
     {
@@ -1000,7 +1000,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns discount_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountRefunded()
     {
@@ -1010,7 +1010,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns event_id
      *
-     * @return int
+     * @return int|null
      */
     public function getEventId()
     {
@@ -1020,7 +1020,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns ext_order_item_id
      *
-     * @return string
+     * @return string|null
      */
     public function getExtOrderItemId()
     {
@@ -1030,7 +1030,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns free_shipping
      *
-     * @return int
+     * @return int|null
      */
     public function getFreeShipping()
     {
@@ -1040,7 +1040,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_base_price
      *
-     * @return float
+     * @return float|null
      */
     public function getGwBasePrice()
     {
@@ -1050,7 +1050,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_base_price_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getGwBasePriceInvoiced()
     {
@@ -1060,7 +1060,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_base_price_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getGwBasePriceRefunded()
     {
@@ -1070,7 +1070,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_base_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getGwBaseTaxAmount()
     {
@@ -1080,7 +1080,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_base_tax_amount_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getGwBaseTaxAmountInvoiced()
     {
@@ -1090,7 +1090,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_base_tax_amount_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getGwBaseTaxAmountRefunded()
     {
@@ -1100,7 +1100,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_id
      *
-     * @return int
+     * @return int|null
      */
     public function getGwId()
     {
@@ -1110,7 +1110,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_price
      *
-     * @return float
+     * @return float|null
      */
     public function getGwPrice()
     {
@@ -1120,7 +1120,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_price_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getGwPriceInvoiced()
     {
@@ -1130,7 +1130,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_price_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getGwPriceRefunded()
     {
@@ -1140,7 +1140,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getGwTaxAmount()
     {
@@ -1150,7 +1150,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_tax_amount_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getGwTaxAmountInvoiced()
     {
@@ -1160,7 +1160,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns gw_tax_amount_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getGwTaxAmountRefunded()
     {
@@ -1170,7 +1170,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns discount_tax_compensation_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationAmount()
     {
@@ -1180,7 +1180,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns discount_tax_compensation_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationCanceled()
     {
@@ -1190,7 +1190,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns discount_tax_compensation_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationInvoiced()
     {
@@ -1200,7 +1200,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns discount_tax_compensation_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getDiscountTaxCompensationRefunded()
     {
@@ -1210,7 +1210,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns is_qty_decimal
      *
-     * @return int
+     * @return int|null
      */
     public function getIsQtyDecimal()
     {
@@ -1220,7 +1220,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns is_virtual
      *
-     * @return int
+     * @return int|null
      */
     public function getIsVirtual()
     {
@@ -1230,7 +1230,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns item_id
      *
-     * @return int
+     * @return int|null
      */
     public function getItemId()
     {
@@ -1240,7 +1240,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns locked_do_invoice
      *
-     * @return int
+     * @return int|null
      */
     public function getLockedDoInvoice()
     {
@@ -1250,7 +1250,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns locked_do_ship
      *
-     * @return int
+     * @return int|null
      */
     public function getLockedDoShip()
     {
@@ -1260,7 +1260,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns name
      *
-     * @return string
+     * @return string|null
      */
     public function getName()
     {
@@ -1270,7 +1270,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns no_discount
      *
-     * @return int
+     * @return int|null
      */
     public function getNoDiscount()
     {
@@ -1280,7 +1280,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns order_id
      *
-     * @return int
+     * @return int|null
      */
     public function getOrderId()
     {
@@ -1290,7 +1290,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns parent_item_id
      *
-     * @return int
+     * @return int|null
      */
     public function getParentItemId()
     {
@@ -1300,7 +1300,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns price
      *
-     * @return float
+     * @return float|null
      */
     public function getPrice()
     {
@@ -1310,7 +1310,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns price_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getPriceInclTax()
     {
@@ -1320,7 +1320,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns product_id
      *
-     * @return int
+     * @return int|null
      */
     public function getProductId()
     {
@@ -1330,7 +1330,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns product_type
      *
-     * @return string
+     * @return string|null
      */
     public function getProductType()
     {
@@ -1340,7 +1340,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns qty_backordered
      *
-     * @return float
+     * @return float|null
      */
     public function getQtyBackordered()
     {
@@ -1350,7 +1350,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns qty_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getQtyCanceled()
     {
@@ -1360,7 +1360,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns qty_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getQtyInvoiced()
     {
@@ -1370,7 +1370,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns qty_ordered
      *
-     * @return float
+     * @return float|null
      */
     public function getQtyOrdered()
     {
@@ -1380,7 +1380,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns qty_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getQtyRefunded()
     {
@@ -1390,7 +1390,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns qty_returned
      *
-     * @return float
+     * @return float|null
      */
     public function getQtyReturned()
     {
@@ -1400,7 +1400,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns qty_shipped
      *
-     * @return float
+     * @return float|null
      */
     public function getQtyShipped()
     {
@@ -1410,7 +1410,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns quote_item_id
      *
-     * @return int
+     * @return int|null
      */
     public function getQuoteItemId()
     {
@@ -1420,7 +1420,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns row_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getRowInvoiced()
     {
@@ -1430,7 +1430,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns row_total
      *
-     * @return float
+     * @return float|null
      */
     public function getRowTotal()
     {
@@ -1440,7 +1440,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns row_total_incl_tax
      *
-     * @return float
+     * @return float|null
      */
     public function getRowTotalInclTax()
     {
@@ -1450,7 +1450,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns row_weight
      *
-     * @return float
+     * @return float|null
      */
     public function getRowWeight()
     {
@@ -1470,7 +1470,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns store_id
      *
-     * @return int
+     * @return int|null
      */
     public function getStoreId()
     {
@@ -1480,7 +1480,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns tax_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxAmount()
     {
@@ -1490,7 +1490,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns tax_before_discount
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxBeforeDiscount()
     {
@@ -1500,7 +1500,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns tax_canceled
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxCanceled()
     {
@@ -1510,7 +1510,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns tax_invoiced
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxInvoiced()
     {
@@ -1520,7 +1520,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns tax_percent
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxPercent()
     {
@@ -1530,7 +1530,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns tax_refunded
      *
-     * @return float
+     * @return float|null
      */
     public function getTaxRefunded()
     {
@@ -1540,7 +1540,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns updated_at
      *
-     * @return string
+     * @return string|null
      */
     public function getUpdatedAt()
     {
@@ -1550,7 +1550,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns weee_tax_applied
      *
-     * @return string
+     * @return string|null
      */
     public function getWeeeTaxApplied()
     {
@@ -1560,7 +1560,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns weee_tax_applied_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getWeeeTaxAppliedAmount()
     {
@@ -1570,7 +1570,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns weee_tax_applied_row_amount
      *
-     * @return float
+     * @return float|null
      */
     public function getWeeeTaxAppliedRowAmount()
     {
@@ -1580,7 +1580,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns weee_tax_disposition
      *
-     * @return float
+     * @return float|null
      */
     public function getWeeeTaxDisposition()
     {
@@ -1590,7 +1590,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns weee_tax_row_disposition
      *
-     * @return float
+     * @return float|null
      */
     public function getWeeeTaxRowDisposition()
     {
@@ -1600,7 +1600,7 @@ class Item extends AbstractModel implements OrderItemInterface
     /**
      * Returns weight
      *
-     * @return float
+     * @return float|null
      */
     public function getWeight()
     {
diff --git a/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/CreditmemoGetTest.php b/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/CreditmemoGetTest.php
index e5a452df8c0ac289ec5bb1193afb1025cc7e98b3..b567d9a5110952adeac8ae66331d8c210cfb4480 100644
--- a/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/CreditmemoGetTest.php
+++ b/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/CreditmemoGetTest.php
@@ -105,5 +105,10 @@ class CreditmemoGetTest extends WebapiAbstract
             $this->assertArrayHasKey($field, $actual);
             $this->assertEquals($expected[$field], $actual[$field]);
         }
+
+        //check that nullable fields were marked as optional and were not sent
+        foreach ($actual as $value) {
+            $this->assertNotNull($value);
+        }
     }
 }
diff --git a/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/InvoiceGetTest.php b/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/InvoiceGetTest.php
index 912f222a8e8f28ac34859cfaf722f9dff78b264e..030ed01fd1a77c03612c8e8453e2c1622f92d7d1 100644
--- a/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/InvoiceGetTest.php
+++ b/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/InvoiceGetTest.php
@@ -48,5 +48,10 @@ class InvoiceGetTest extends WebapiAbstract
             $this->assertArrayHasKey($field, $result);
             $this->assertEquals($value, $result[$field]);
         }
+
+        //check that nullable fields were marked as optional and were not sent
+        foreach ($result as $value) {
+            $this->assertNotNull($value);
+        }
     }
 }
diff --git a/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/OrderGetTest.php b/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/OrderGetTest.php
index f71b6cbec323dde7df02b777b44397ad1a314cb4..4526e48fdacfcbbaaa56955d4c9cd88b294b70d1 100644
--- a/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/OrderGetTest.php
+++ b/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/OrderGetTest.php
@@ -81,5 +81,10 @@ class OrderGetTest extends WebapiAbstract
         foreach ($expectedBillingAddressNotEmpty as $field) {
             $this->assertArrayHasKey($field, $result['billing_address']);
         }
+
+        //check that nullable fields were marked as optional and were not sent
+        foreach ($result as $value) {
+            $this->assertNotNull($value);
+        }
     }
 }
diff --git a/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/OrderItemGetTest.php b/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/OrderItemGetTest.php
index 88a94ca32fc50ed7969d99c2db75295e6a4c0d0d..7831c10ff3ae58b2701ad43642f608ded92be8be 100644
--- a/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/OrderItemGetTest.php
+++ b/dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/OrderItemGetTest.php
@@ -53,6 +53,14 @@ class OrderItemGetTest extends WebapiAbstract
 
         $this->assertTrue(is_array($response));
         $this->assertOrderItem($orderItem, $response);
+
+        //check that nullable fields were marked as optional and were not sent
+        foreach ($response as $fieldName => $value) {
+            if ($fieldName == 'sku') {
+                continue;
+            }
+            $this->assertNotNull($value);
+        }
     }
 
     /**