As easy as a button press.
It's confession time. I've had Bluetooth Xbox One controllers for years, but never knew how to turn them off via Bluetooth on mobile or PC without yanking the batteries. On Xbox, you simply hold the button, and it opens a new menu allowing you to turn it off. On mobile phones with Project xCloud and on PCs with Bluetooth, however, you don't get any such menu.
Turns out, that it's actually incredibly easy to solve, with a quick 6-second Xbox button press.
Full story from the WindowsCentral blog...