func resource_aws_internet_gateway_detach(
	ec2conn *ec2.EC2,
	s *terraform.ResourceState) error {
	if s.Attributes["vpc_id"] == "" {
		return nil
	}

	log.Printf(
		"[INFO] Detaching Internet Gateway '%s' from VPC '%s'",
		s.ID,
		s.Attributes["vpc_id"])
	wait := true
	_, err := ec2conn.DetachInternetGateway(s.ID, s.Attributes["vpc_id"])
	if err != nil {
		ec2err, ok := err.(*ec2.Error)
		if ok {
			if ec2err.Code == "InvalidInternetGatewayID.NotFound" {
				err = nil
				wait = false
			} else if ec2err.Code == "Gateway.NotAttached" {
				err = nil
				wait = false
			}
		}

		if err != nil {
			return err
		}
	}

	delete(s.Attributes, "vpc_id")

	if !wait {
		return nil
	}

	// Wait for it to be fully detached before continuing
	log.Printf("[DEBUG] Waiting for internet gateway (%s) to detach", s.ID)
	stateConf := &resource.StateChangeConf{
		Pending: []string{"attached", "detaching", "available"},
		Target:  "detached",
		Refresh: IGAttachStateRefreshFunc(ec2conn, s.ID, "detached"),
		Timeout: 1 * time.Minute,
	}
	if _, err := stateConf.WaitForState(); err != nil {
		return fmt.Errorf(
			"Error waiting for internet gateway (%s) to detach: %s",
			s.ID, err)
	}

	return nil
}