diff --git a/doc/lispref/debugging.texi b/doc/lispref/debugging.texi
index b5a73a255af..5230854cc7a 100644
--- a/doc/lispref/debugging.texi
+++ b/doc/lispref/debugging.texi
@@ -451,7 +451,7 @@ Move to the beginning of the next frame.
 Add line breaks and indentation to the top-level Lisp form at point to
 make it more readable.
 
-@item =
+@item -
 Collapse the top-level Lisp form at point back to a single line.
 
 @item #
diff --git a/lisp/emacs-lisp/backtrace.el b/lisp/emacs-lisp/backtrace.el
index aac43fec8e4..779feb43075 100644
--- a/lisp/emacs-lisp/backtrace.el
+++ b/lisp/emacs-lisp/backtrace.el
@@ -186,7 +186,7 @@ This is commonly used to recompute `backtrace-frames'.")
     (define-key map "#" 'backtrace-toggle-print-circle)
     (define-key map "\C-m" 'backtrace-help-follow-symbol)
     (define-key map "+" 'backtrace-pretty-print)
-    (define-key map "=" 'backtrace-collapse)
+    (define-key map "-" 'backtrace-collapse)
     (define-key map [follow-link] 'mouse-face)
     (define-key map [mouse-2] 'mouse-select-window)
     map)