diff --git a/aws/resource_aws_db_instance.go b/aws/resource_aws_db_instance.go
index 5d5ce8f9c65a..28d177022b06 100644
--- a/aws/resource_aws_db_instance.go
+++ b/aws/resource_aws_db_instance.go
@@ -535,11 +535,12 @@ func resourceAwsDbInstanceCreate(d *schema.ResourceData, meta interface{}) error
 			opts.Iops = aws.Int64(int64(attr.(int)))
 		}
 
+		if arnParts := strings.Split(v.(string), ":"); len(arnParts) >= 4 {
+			opts.SourceRegion = aws.String(arnParts[3])
+		}
+
 		if attr, ok := d.GetOk("kms_key_id"); ok {
 			opts.KmsKeyId = aws.String(attr.(string))
-			if arnParts := strings.Split(v.(string), ":"); len(arnParts) >= 4 {
-				opts.SourceRegion = aws.String(arnParts[3])
-			}
 		}
 
 		if attr, ok := d.GetOk("maintenance_window"); ok {
diff --git a/website/docs/r/db_instance.html.markdown b/website/docs/r/db_instance.html.markdown
index 265e6fd9d54b..19fa1dcd96d9 100644
--- a/website/docs/r/db_instance.html.markdown
+++ b/website/docs/r/db_instance.html.markdown
@@ -115,8 +115,7 @@ identifier beginning with the specified prefix. Conflicts with `identifier`.
 * `instance_class` - (Required) The instance type of the RDS instance.
 * `iops` - (Optional) The amount of provisioned IOPS. Setting this implies a
 storage_type of "io1".
-* `kms_key_id` - (Optional) The ARN for the KMS encryption key. If creating an
-encrypted replica, set this to the destination KMS ARN.
+* `kms_key_id` - (Optional) The ARN for the KMS encryption key.
 * `license_model` - (Optional, but required for some DB engines, i.e. Oracle
 SE1) License model information for this DB instance.
 * `maintenance_window` - (Optional) The window to perform maintenance in.
@@ -147,8 +146,7 @@ accessible. Default is `false`.
 * `replicate_source_db` - (Optional) Specifies that this resource is a Replicate
 database, and to use this value as the source database. This correlates to the
 `identifier` of another Amazon RDS Database to replicate. Note that if you are
-creating a cross-region replica of an encrypted database you will also need to
-specify a `kms_key_id`. See [DB Instance Replication][1] and [Working with
+creating a cross-region replica it must be an arn. See [DB Instance Replication][1] and [Working with
 PostgreSQL and MySQL Read Replicas](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html)
 for more information on using Replication.
 * `security_group_names` - (Optional/Deprecated) List of DB Security Groups to
@@ -163,9 +161,7 @@ is `false`.
 database from a snapshot. This correlates to the snapshot ID you'd find in the
 RDS console, e.g: rds:production-2015-06-26-06-05.
 * `storage_encrypted` - (Optional) Specifies whether the DB instance is
-encrypted. Note that if you are creating a cross-region read replica this field
-is ignored and you should instead declare `kms_key_id` with a valid ARN. The
-default is `false` if not specified.
+encrypted. The default is `false` if not specified.
 * `storage_type` - (Optional) One of "standard" (magnetic), "gp2" (general
 purpose SSD), or "io1" (provisioned IOPS SSD). The default is "io1" if `iops` is
 specified, "gp2" if not.