ido-ignore-files

ido-ignore-files is a variable defined in `ido.el'.
Its value is

("\\`CVS/" "\\`#" "\\`.#" "\\`\\.\\./" "\\`\\./")

Documentation:
List of regexps or functions matching file names to ignore.
For example, traditional behavior is not to list files whose names begin
with a #, for which the regexp is `\`#'. See the source file for
example functions that filter filenames.

You can customize this variable.