diff --git a/activejob/lib/active_job/arguments.rb b/activejob/lib/active_job/arguments.rb
index 622c37098e43134c81fc9d216a4a44789ed3117a..f9392cf278fd9ec0d40bb4fe5d3cbc7fdc59b06b 100644
--- a/activejob/lib/active_job/arguments.rb
+++ b/activejob/lib/active_job/arguments.rb
@@ -24,6 +24,7 @@ class SerializationError < ArgumentError
 
   module Arguments
     extend self
+    # :nodoc:
     TYPE_WHITELIST = [ NilClass, Fixnum, Float, String, TrueClass, FalseClass, Bignum ]
 
     # Serializes a set of arguments. Whitelisted types are returned
@@ -43,8 +44,11 @@ def deserialize(arguments)
     end
 
     private
+      # :nodoc:
       GLOBALID_KEY = '_aj_globalid'.freeze
+      # :nodoc:
       SYMBOL_KEYS_KEY = '_aj_symbol_keys'.freeze
+      # :nodoc:
       WITH_INDIFFERENT_ACCESS_KEY = '_aj_hash_with_indifferent_access'.freeze
       private_constant :GLOBALID_KEY, :SYMBOL_KEYS_KEY, :WITH_INDIFFERENT_ACCESS_KEY
 
@@ -113,6 +117,7 @@ def deserialize_hash(serialized_hash)
         result
       end
 
+      # :nodoc:
       RESERVED_KEYS = [
         GLOBALID_KEY, GLOBALID_KEY.to_sym,
         SYMBOL_KEYS_KEY, SYMBOL_KEYS_KEY.to_sym,