If it's written, it's copyrighted.
[link|http://www4.law.cornell.edu/uscode/17/102.html|17 USC 102(a)]:
Copyright protection subsists, in accordance with this title, in original works of authorship fixed in any tangible medium of expression, now known or later developed, from which they can be perceived, reproduced, or otherwise communicated, either directly or with the
aid of a machine or device. Works of authorship include the following categories:
(1) literary works;
(2) musical works, including any accompanying words;
(3) dramatic works, including any accompanying music;
(4) pantomimes and choreographic works;
(5) pictorial, graphic, and sculptural works;
(6) motion pictures and other audiovisual works;
(7) sound recordings; and
(8) architectural works.
Emphasis added.
Fixation is the key.
This is a work governed by copyright.
There are limitations. If you're a federal government employee, you belong to one of the few classes of people who may create works
not governed by copyright, and there are exemptions to copyright protections. See link above for details.
Works for hire are owned by your employer.