Q: iPhone 6 Bluetooth not detecting any device

Make sure the device you're trying to pair your phone with is also detectable.

I have the exact same problem!  The odd thing is, last week I was able to use the Bluetooth for my vehicle AND for my wireless headphones, then one day NO devices could be found.  It just continually searches; it doesn't even tell you there are no devices found, like it used to say when nothing was in range.  It's quite frustrating.  I've done all of the "fixes" on the Apple Support page, including restoring it back to factory settings via iTunes, but nothing has worked.  I guess my next step is hitting the Apple store.