diff --git a/website/docs/r/api_gateway_api_key.html.markdown b/website/docs/r/api_gateway_api_key.html.markdown
index 38672b55956d..cd2327b283cb 100644
--- a/website/docs/r/api_gateway_api_key.html.markdown
+++ b/website/docs/r/api_gateway_api_key.html.markdown
@@ -25,7 +25,7 @@ resource "aws_api_gateway_api_key" "example" {
 This resource supports the following arguments:
 
 * `name` - (Required) Name of the API key.
-* `customer_id` - (Required) An Amazon Web Services Marketplace customer identifier, when integrating with the Amazon Web Services SaaS Marketplace.
+* `customer_id` - (Optional) An Amazon Web Services Marketplace customer identifier, when integrating with the Amazon Web Services SaaS Marketplace.
 * `description` - (Optional) API key description. Defaults to "Managed by Terraform".
 * `enabled` - (Optional) Whether the API key can be used by callers. Defaults to `true`.
 * `value` - (Optional) Value of the API key. If specified, the value must be an alphanumeric string between 20 and 128 characters. If not specified, it will be automatically generated by AWS on creation.