From The Document Foundation Wiki
How to install LibreOffice on SteamOS
SteamOS is now in public beta. Here's how to run LibreOffice on SteamOS.
- Follow the excellent guide on how to get and install SteamOS here. Replace the package name xorg-xserver by xserver-xorg in the doc
- while still in recovery mode, set a root password: passwd
- login as user desktop, start a terminal
- su with the root password
- nano -w /etc/apt/sources.list
- add "deb http://http.debian.net/debian wheezy main" to file (maybe this is not even needed)
- add "deb http://ftp.debian.org/debian/ wheezy-backports main" to file and save
- apt-get update
- apt-get -t wheezy-backports install libreoffice
and voilà, LibreOffice should run perfectly!