How do I turn off my Xbox One controller?

How do I turn off my Xbox One controller?
When the controller is turned on:

Pressing this button once will open the guide on the Xbox console.
Pressing and holding this button will open the What do you want to do?
Pressing and holding this button for about 6 seconds turns off the controller.

When the controller is turned on:
  1. Pressing this button once will open the guide on the Xbox console.
  2. Pressing and holding this button will open the What do you want to do?
  3. Pressing and holding this button for about 6 seconds turns off the controller.