I thought Christian doctrine was quite explicit that unless you accept Jesus as Savior you are doomed to Hell.
If you have never heard the name Jesus (say you live in a tribe in Africa) then what? Yes, if God has revealed Jesus to you, then there is no excuse. But there may be many circumstances that would not warrant eternal damnation for humans if they had not accepted Jesus...this is up to God. I assure you, a 3 year old who has not accepted Jesus will not go to hell. That isn't God's way. How He would determine who goes and who doesn't is up to Him. I am not even going to think I can rationalize the thoughts of God.
Do all Muslims go to hell? Heck, I don't know. It's not up to me, but I don't believe that all Muslims go to hell. Am I right? I don't know.