diff --git a/README.md b/README.md
index 485a805..e3b5bc6 100644
--- a/README.md
+++ b/README.md
@@ -287,7 +287,7 @@ Available targets:
 | <a name="input_metrics_granularity"></a> [metrics\_granularity](#input\_metrics\_granularity) | The granularity to associate with the metrics to collect. The only valid value is 1Minute | `string` | `"1Minute"` | no |
 | <a name="input_min_elb_capacity"></a> [min\_elb\_capacity](#input\_min\_elb\_capacity) | Setting this causes Terraform to wait for this number of instances to show up healthy in the ELB only on creation. Updates will not wait on ELB instance number changes | `number` | `0` | no |
 | <a name="input_min_size"></a> [min\_size](#input\_min\_size) | The minimum size of the autoscale group | `number` | n/a | yes |
-| <a name="input_mixed_instances_policy"></a> [mixed\_instances\_policy](#input\_mixed\_instances\_policy) | policy to used mixed group of on demand/spot of differing types. Launch template is automatically generated. https://www.terraform.io/docs/providers/aws/r/autoscaling_group.html#mixed_instances_policy-1 | <pre>object({<br>    instances_distribution = object({<br>      on_demand_allocation_strategy            = string<br>      on_demand_base_capacity                  = number<br>      on_demand_percentage_above_base_capacity = number<br>      spot_allocation_strategy                 = string<br>      spot_instance_pools                      = number<br>      spot_max_price                           = string<br>    })<br>    override = list(object({<br>      instance_type     = string<br>      weighted_capacity = number<br>    }))<br>  })</pre> | `null` | no |
+| <a name="input_mixed_instances_policy"></a> [mixed\_instances\_policy](#input\_mixed\_instances\_policy) | policy to used mixed group of on demand/spot of differing types. Launch template is automatically generated. https://www.terraform.io/docs/providers/aws/r/autoscaling_group.html#mixed_instances_policy-1 | <pre>object({<br>    instances_distribution = optional(object({<br>      on_demand_allocation_strategy            = string<br>      on_demand_base_capacity                  = number<br>      on_demand_percentage_above_base_capacity = number<br>      spot_allocation_strategy                 = string<br>      spot_instance_pools                      = number<br>      spot_max_price                           = string<br>    }))<br>    override = optional(list(object({<br>      instance_type     = string<br>      weighted_capacity = number<br>    })))<br>  })</pre> | `null` | no |
 | <a name="input_name"></a> [name](#input\_name) | ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'.<br>This is the only ID element not also included as a `tag`.<br>The "name" tag is set to the full `id` string. There is no tag with the value of the `name` input. | `string` | `null` | no |
 | <a name="input_namespace"></a> [namespace](#input\_namespace) | ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique | `string` | `null` | no |
 | <a name="input_network_interface_id"></a> [network\_interface\_id](#input\_network\_interface\_id) | The ID of the network interface to attach. If specified, all the other network\_interface block arguments are ignored. | `string` | `null` | no |
diff --git a/docs/terraform.md b/docs/terraform.md
index 89a819a..b54215a 100644
--- a/docs/terraform.md
+++ b/docs/terraform.md
@@ -90,7 +90,7 @@
 | <a name="input_metrics_granularity"></a> [metrics\_granularity](#input\_metrics\_granularity) | The granularity to associate with the metrics to collect. The only valid value is 1Minute | `string` | `"1Minute"` | no |
 | <a name="input_min_elb_capacity"></a> [min\_elb\_capacity](#input\_min\_elb\_capacity) | Setting this causes Terraform to wait for this number of instances to show up healthy in the ELB only on creation. Updates will not wait on ELB instance number changes | `number` | `0` | no |
 | <a name="input_min_size"></a> [min\_size](#input\_min\_size) | The minimum size of the autoscale group | `number` | n/a | yes |
-| <a name="input_mixed_instances_policy"></a> [mixed\_instances\_policy](#input\_mixed\_instances\_policy) | policy to used mixed group of on demand/spot of differing types. Launch template is automatically generated. https://www.terraform.io/docs/providers/aws/r/autoscaling_group.html#mixed_instances_policy-1 | <pre>object({<br>    instances_distribution = object({<br>      on_demand_allocation_strategy            = string<br>      on_demand_base_capacity                  = number<br>      on_demand_percentage_above_base_capacity = number<br>      spot_allocation_strategy                 = string<br>      spot_instance_pools                      = number<br>      spot_max_price                           = string<br>    })<br>    override = list(object({<br>      instance_type     = string<br>      weighted_capacity = number<br>    }))<br>  })</pre> | `null` | no |
+| <a name="input_mixed_instances_policy"></a> [mixed\_instances\_policy](#input\_mixed\_instances\_policy) | policy to used mixed group of on demand/spot of differing types. Launch template is automatically generated. https://www.terraform.io/docs/providers/aws/r/autoscaling_group.html#mixed_instances_policy-1 | <pre>object({<br>    instances_distribution = optional(object({<br>      on_demand_allocation_strategy            = string<br>      on_demand_base_capacity                  = number<br>      on_demand_percentage_above_base_capacity = number<br>      spot_allocation_strategy                 = string<br>      spot_instance_pools                      = number<br>      spot_max_price                           = string<br>    }))<br>    override = optional(list(object({<br>      instance_type     = string<br>      weighted_capacity = number<br>    })))<br>  })</pre> | `null` | no |
 | <a name="input_name"></a> [name](#input\_name) | ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'.<br>This is the only ID element not also included as a `tag`.<br>The "name" tag is set to the full `id` string. There is no tag with the value of the `name` input. | `string` | `null` | no |
 | <a name="input_namespace"></a> [namespace](#input\_namespace) | ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique | `string` | `null` | no |
 | <a name="input_network_interface_id"></a> [network\_interface\_id](#input\_network\_interface\_id) | The ID of the network interface to attach. If specified, all the other network\_interface block arguments are ignored. | `string` | `null` | no |
diff --git a/variables.tf b/variables.tf
index 91c6b22..f89dbf6 100644
--- a/variables.tf
+++ b/variables.tf
@@ -136,18 +136,18 @@ variable "mixed_instances_policy" {
   description = "policy to used mixed group of on demand/spot of differing types. Launch template is automatically generated. https://www.terraform.io/docs/providers/aws/r/autoscaling_group.html#mixed_instances_policy-1"
 
   type = object({
-    instances_distribution = object({
+    instances_distribution = optional(object({
       on_demand_allocation_strategy            = string
       on_demand_base_capacity                  = number
       on_demand_percentage_above_base_capacity = number
       spot_allocation_strategy                 = string
       spot_instance_pools                      = number
       spot_max_price                           = string
-    })
-    override = list(object({
+    }))
+    override = optional(list(object({
       instance_type     = string
       weighted_capacity = number
-    }))
+    })))
   })
   default = null
 }