diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index cb5fa43..b3262b2 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -1862,6 +1862,7 @@
 bufloaded({expr})		Number	TRUE if buffer {expr} is loaded
 bufname({expr})			String	Name of the buffer {expr}
 bufnr({expr} [, {create}])	Number	Number of the buffer {expr}
+bufwinid({expr})		Number	window ID of buffer {expr}
 bufwinnr({expr})		Number	window number of buffer {expr}
 byte2line({byte})		Number	line number at byte count {byte}
 byteidx({expr}, {nr})		Number	byte index of {nr}'th char in {expr}
@@ -2557,6 +2558,16 @@
 							*last_buffer_nr()*
 		Obsolete name for bufnr("$"): last_buffer_nr().
 
+bufwinid({expr})					*bufwinid()*
+		The result is a Number, which is the window ID of the first
+		window associated with buffer {expr}.  For the use of {expr},
+		see |bufname()| above.	If buffer {expr} doesn't exist or
+		there is no such window, -1 is returned.  Example: >
+
+	echo "A window containing buffer 1 is " . (bufwinid(1))
+<
+		Only deals with the current tab page.
+
 bufwinnr({expr})					*bufwinnr()*
 		The result is a Number, which is the number of the first
 		window associated with buffer {expr}.  For the use of {expr},