The link above given by Salah is old and doesn't apply to recent releases. The Start screen can be turned off in General Preferences. Look for the checkbox at the top titled 'Show "Start" Workspace When No Documents Are Open' and un-check it.
If, by that, you mean Edit>>Preferences>>General, there is no such checkbox on my version CC 2014. If you mean something else by "General Preferences", where can I find that?
Dang, I didn't read the title of this thread closely enough. For InDesign CC 2014, the link provided by Salah is correct. To save you from reading through it all, Here's what you need to do:
1.) Make sure that you're actually logged into Creative Cloud from within InDesign. Check the Help menu and be sure that you see "Sign Out (Your Adobe ID Here)". If it instead says "Sign In", then you should select that menu item and sign in properly.
2.) Now quit and relaunch InDesign. At the bottom of the 'New Features' tab, you should now see the option to turn off Welcome screen.