diff --git a/sklearn/linear_model/stochastic_gradient.py b/sklearn/linear_model/stochastic_gradient.py
index 25eee3b131b3e..a0429fa37470f 100644
--- a/sklearn/linear_model/stochastic_gradient.py
+++ b/sklearn/linear_model/stochastic_gradient.py
@@ -987,6 +987,20 @@ def decision_function(self, X):
         ----------
         X : {array-like, sparse matrix}, shape (n_samples, n_features)
 
+        Returns
+        -------
+        array, shape (n_samples,)
+           Predicted target values per element in X.
+        """
+        return self._decision_function(X)
+
+    def _decision_function(self, X):
+        """Predict using the linear model
+
+        Parameters
+        ----------
+        X : {array-like, sparse matrix}, shape (n_samples, n_features)
+
         Returns
         -------
         array, shape (n_samples,)
@@ -1012,7 +1026,7 @@ def predict(self, X):
         array, shape (n_samples,)
            Predicted target values per element in X.
         """
-        return self.decision_function(X)
+        return self._decision_function(X)
 
     def _fit_regressor(self, X, y, alpha, C, loss, learning_rate,
                        sample_weight, n_iter):