diff --git a/README.md b/README.md
index a7704148a4..0d67023e74 100644
--- a/README.md
+++ b/README.md
@@ -2074,11 +2074,12 @@ const promise = mutate(variables, {
   - The mutation function you can call with variables to trigger the mutation and optionally override the original mutation options.
 - `status: String`
   - Will be:
+    - `idle` initial status prior to the mutation function executing.
     - `loading` if the mutation is currently executing.
     - `error` if the last mutation attempt resulted in an error.
     - `success' if the last mutation attempt was successful.
-- `data: null | Any`
-  - Defaults to `null`
+- `data: undefined | Any`
+  - Defaults to `undefined`
   - The last successfully resolved data for the query.
 - `error: null | Error`
   - The error object for the query, if an error was encountered.