diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 8264a39..5a04f39 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -332,6 +332,18 @@
 
    .. versionadded:: 2.6
 
+.. data:: float_repr_style
+
+   A string indicating how the :func:`repr` function behaves for
+   floats.  If the string has value ``'short'`` then for a finite
+   float ``x``, ``repr(x)`` aims to produce a short string with the
+   property that ``float(repr(x)) == x``.  This is the usual behaviour
+   in Python 2.7 and later.  Otherwise, ``float_repr_style`` has value
+   ``'legacy'`` and ``repr(x)`` behaves in the same way as it did in
+   versions of Python prior to 2.7.
+
+   .. versionadded:: 2.7
+
 
 .. function:: getcheckinterval()