You can't backup one iPhone with another iPhone. The backup for each iOS device is created and stored separately.
Do you mean you restored your iPhone with iTunes with the backup for another iPhone?
The backup for each iOS device is created and stored separately.
When restoring an iPhone with iTunes when there is more than one backup available, you can select the backup you want to restore the iPhone with. Restore the iPhone with iTunes again and this time select the correct iPhone backup when prompted.