There are two things I did with Ivy, and I recommend you do them, too:
1) I am the boss of everything. From the very first day, I taught her to Sit or Down when she wanted something. If she wanted dinner, she had to Sit and she had to Wait. Today, she will not eat her dinner unless I explicitly say "Okay!" and release her from her Sit/Wait. She also sits before exiting the house, before getting a toy, before putting her collar on, etc. This method is called Nothing In Life Is Free: www.k9deb.com/nilif.htm
2) Give means GIVE. One of my biggest fears was raising a large-breed puppy who didn't know "Give". As a result, I taught Ivy "Give" from the day she came home. I would give her a toy and let her play with it. Once the toy was firmly in her mouth, I held a piece of chicken (tip: real meat is the best motivator) in front of her nose and said "GIVE". She instinctively dropped the toy and went for the treat. Repeat repeat repeat. Eventually, say "Give" without the treat. The dog should give the toy up willingly. Over time, generalize the behavior - meaning, try asking for a "Give" with all types of items in all types of situations.

Once you have these two things down, Reilly will never resort to biting you for taking away his toy (or cellphone)