Stop Xbox One controller from controlling Windows 10

Turns out it was the new Steam "Xbox Configuration Support" feature. I disabled it and now the controller doesn't do anything in Windows and all my games work again.

Before (with Issue):

After (Without Issue):

If you want to keep Steam's "XBox configuration support" enabled (which is useful for things like calibrating dead zones + some games require it) and still disable the controllers from controlling your mouse and keyboard:

1. From the steam main application (not Big Picture) click "Steam" in the upper left corner
2. Click "settings"
3. Click the "controller" tab
4. Click Desktop Configuration
5. Select each of the fields that say for example "Mouse button 1" or "Left ctrl" and use your xbox controller to press the button for "remove" (I had some issues using the mouse in this menu). Some fields have sub-fields and you need to remove those too.
6. Press the back button (default: (B) ) on your controller until you exit the special menu.
7. You're all done :)