diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -701,21 +701,29 @@
 
 .. attribute:: Popen.stdin
 
-   If the *stdin* argument was :data:`PIPE`, this attribute is a :term:`file
-   object` that provides input to the child process.  Otherwise, it is ``None``.
+   If the *stdin* argument was :data:`PIPE`, this attribute is a
+   :class:`io.BufferedWriter` (if the *universal_newlines* argument
+   was False) or :class:`io.TextIOWrapper` (if the
+   *universal_newlines* argument was True) object that provides input
+   to the child process. Otherwise, it is ``None``.
 
 
 .. attribute:: Popen.stdout
 
-   If the *stdout* argument was :data:`PIPE`, this attribute is a :term:`file
-   object` that provides output from the child process.  Otherwise, it is ``None``.
+   If the *stdout* argument was :data:`PIPE`, this attribute is a
+   :class:`io.BufferedReader` (if the *universal_newlines* argument
+   was False) or :class:`io.TextIOWrapper` (if the
+   *universal_newlines* argument was True) object that provides output
+   from the child process. Otherwise, it is ``None``.
 
 
 .. attribute:: Popen.stderr
 
-   If the *stderr* argument was :data:`PIPE`, this attribute is a :term:`file
-   object` that provides error output from the child process.  Otherwise, it is
-   ``None``.
+   If the *stderr* argument was :data:`PIPE`, this attribute is a
+   :class:`io.BufferedReader` (if the *universal_newlines* argument
+   was False) or :class:`io.TextIOWrapper` (if the
+   *universal_newlines* argument was True) object that provides output
+   from the child process. Otherwise, it is ``None``.
 
 
 .. attribute:: Popen.pid