There's a passage where Jesus says, "No one comes to to Father but by me," which we were taught meant that you had to believe in Jesus to get to heaven.
Over the years I've been surprised to run into Christians who don't believe this - that you can get into heaven if you're not a Christian. That confused me, as I always saw that as one of the central tenets of Christianity.
I can tell you this much from the perspective of the Freak-Ass Church*, which is Protestant nondenominational, very evangelical, and very literal bible interpretation:
The simple answer is yes, they believe that non-Christians (i.e., those who do not accept Jesus as their savior) will go to hell. Just calling yourself a "Christian" and going to church every Sunday doesn't guarantee that you're a "Christian" by the accept-Jesus definition, and really, what ensures a seat in heaven is accepting Jesus, regardless of what you call yourself.
So, simple answer -- yes. Non-Christians will fry.
Less simple answer, which even the FAC recognized is a legitimate viewpoint: if you take the bible literally, it does say that no one comes to the Father (i.e., heaven) except through Jesus. It absolutely does.
However, here's the thing: the bible isn't real clear on what parameters make up the "through Jesus" part. It's pretty likely, however, that it isn't a narrowly defined thing, like you must say certain words, in front of a church full of people, and then get dunked in a holy pool, etc., etc., etc.
A controversial viewpoint is that maybe you don't even have to go "through Jesus" while you're alive. (I believe CS Lewis made that point, though it could have been Francis Schaeffer.) Because if there's *anything* we don't know, it's what happens after the monitor flatlines. Combine that uncertainty with the lack of specificity around "No one comes to the Father but through Jesus," and it's not at all outside the realm of possibility that "through Jesus" could occur after death. Or, at least, that post-death is one of the *options* to go "through Jesus."
I think the lack of specificity around "No one comes to the Father but through Jesus," was designed to have the exact opposite effect of the one it has now, in America, which is more or less a checklist of what you must do and say and how you must do it and say it in order to be a "Christian." I think "No one comes to the Father but through Jesus" very deliberately came without an instruction manual (or at least a long explicated paragraph explaining loopholes and exceptions), because there's more than one way for that to happen. There is probably an infinite number of ways, because God wants everyone. And if God wants everyone, and given that God made us all different and weird and almost incomprehensibly complex, then God is going to allow for -- and provide -- as many ways for us to come "through Jesus" as are needed to suit the crazy complex mess of humanity.
I could, however, be entirely full of shit, so please don't base your hope of eternal life on me.
*(I am speaking ONLY from *my* FAC's viewpoint, not the viewpoint of all Christians, all Protestants, all evangelicals, or even all FACs.)