diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -934,9 +934,9 @@
 (4)
    The slice of *s* from *i* to *j* is defined as the sequence of items with index
    *k* such that ``i <= k < j``.  If *i* or *j* is greater than ``len(s)``, use
-   ``len(s)``.  If *i* is omitted or ``None``, use ``0``.  If *j* is omitted or
-   ``None``, use ``len(s)``.  If *i* is greater than or equal to *j*, the slice is
-   empty.
+   ``len(s)``. If ``len(s) + i`` or ``len(s) + j`` is negative, use ``0``. If *i*
+   is omitted or ``None``, use ``0``.  If *j* is omitted or ``None``, use
+   ``len(s)``.  If *i* is greater than or equal to *j*, the slice is empty.
 
 (5)
    The slice of *s* from *i* to *j* with step *k* is defined as the sequence of