diff --git a/examples/complete/main.tf b/examples/complete/main.tf
index 7a25e467c..b4a8c012c 100644
--- a/examples/complete/main.tf
+++ b/examples/complete/main.tf
@@ -64,6 +64,10 @@ module "vpc" {
       bgp_asn    = 65112
       ip_address = "5.6.7.8"
     }
+    IP3 = {
+      bgp_asn_extended = 2147483648
+      ip_address       = "5.6.7.8"
+    }
   }
 
   enable_vpn_gateway = true
diff --git a/main.tf b/main.tf
index 02f377a3a..31deb5988 100644
--- a/main.tf
+++ b/main.tf
@@ -1290,10 +1290,11 @@ resource "aws_customer_gateway" "this" {
 
   region = var.region
 
-  bgp_asn     = each.value["bgp_asn"]
-  ip_address  = each.value["ip_address"]
-  device_name = lookup(each.value, "device_name", null)
-  type        = "ipsec.1"
+  bgp_asn          = lookup(each.value, "bgp_asn", null)
+  bgp_asn_extended = lookup(each.value, "bgp_asn_extended", null)
+  ip_address       = each.value["ip_address"]
+  device_name      = lookup(each.value, "device_name", null)
+  type             = "ipsec.1"
 
   tags = merge(
     { Name = "${var.name}-${each.key}" },