documents and data taking up 46GB on iPhone 6 64GB

"documents and data" is taking up 46GB on iPhone 6 64GB model(6.3.1 iOS). I cant figure out what it is or how to delete. my iPhone has 0GB free. I have around 2.2GB in Photo, less than 200MB in Music, around 1.2 in Apps, 5.2GB in Other and 46GB in "Documents and Data". How do i find out what it is and how do I delete it? I took it to the Apple store and they suggested I "Reset All Settings" which I just did a few mins ago before posting this. I have a feeling they are going to ask me to Erase all content and settings if I take the phone to the apple store tomorrow.

Steps I did and what I use it for.

-Settings - General - Storage & iCloud Usage, click Manage Storage, all the apps are in the 36KB to 800MB Range totaling around 1GB which doesnt add up to the "Used" section above.

-Icloud Drive is Off, Photos, Mail, Calendars, Safari, icloud backup are all turn off. Just contacts, reminders and notes are sync.

-I only have one exchange mailbox which is set to sync for 1 week only.

-I only have basic applications like facebook, twitter, wall street journal, new york times, google maps.