diff --git a/src/Monolog/ErrorHandler.php b/src/Monolog/ErrorHandler.php
index d0b1aa6d..e8660134 100644
--- a/src/Monolog/ErrorHandler.php
+++ b/src/Monolog/ErrorHandler.php
@@ -49,10 +49,10 @@ class ErrorHandler
      *
      * By default it will handle errors, exceptions and fatal errors
      *
-     * @param  LoggerInterface $logger
-     * @param  array|false     $errorLevelMap     an array of E_* constant to LogLevel::* constant mapping, or false to disable error handling
-     * @param  array|false     $exceptionLevelMap an array of class name to LogLevel::* constant mapping, or false to disable exception handling
-     * @param  int|false       $fatalLevel        a LogLevel::* constant, or false to disable fatal error handling
+     * @param  LoggerInterface   $logger
+     * @param  array|false       $errorLevelMap     an array of E_* constant to LogLevel::* constant mapping, or false to disable error handling
+     * @param  array|false       $exceptionLevelMap an array of class name to LogLevel::* constant mapping, or false to disable exception handling
+     * @param  string|null|false $fatalLevel        a LogLevel::* constant, null to use the default LogLevel::ALERT or false to disable fatal error handling
      * @return ErrorHandler
      */
     public static function register(LoggerInterface $logger, $errorLevelMap = [], $exceptionLevelMap = [], $fatalLevel = null): self
@@ -103,7 +103,11 @@ class ErrorHandler
         return $this;
     }
 
-    public function registerFatalHandler($level = null, $reservedMemorySize = 20): self
+    /**
+     * @param string|null $level a LogLevel::* constant, null to use the default LogLevel::ALERT or false to disable fatal error handling
+     * @param int         $reservedMemorySize Amount of KBs to reserve in memory so that it can be freed when handling fatal errors giving Monolog some room in memory to get its job done
+     */
+    public function registerFatalHandler($level = null, int $reservedMemorySize = 20): self
     {
         register_shutdown_function([$this, 'handleFatalError']);