To make IntelliJ to recognize common Python modules, just create and add Python SDK
File -> Project Structure -> Project -> Project SDK -> new
and select the installation path of your Python interpreter (for example, C:\Python26 in windows and /usr/bin/python2.7 in Linux) as the home path. This allows IntelliJ to look in these directories to give you suggestions and documentation hints.
If your Python SDK is already properly configured and you are still facing the problem that builtins are not recognized, try this:
File -> Invalidate Caches/Restart