That's tricky. I have not fully read the Quran so you should ask someone else. However, I know the Sunnah(which I have not really read much) states that everyone that dies believeing that God has no partners(such as a son, brother, mother, father, sister, spouse, etc.) will receive paradise. They also have to accept all of the prophets.(Abraham, Moses, David, Jesus, Muhammad, etc.) However, if a Jew or a Christian live all their life ignorant to the truth, God will most likely be merciful. However if a Christian or Jew is informed of the truth by somebody, but they are arrogant and don't convert, God will most likely punish them for their disbelief and arrogance in the signs of God. The Quran also refers to Christians and Jews as "people of the book" meaning they have gone astray but will let them practice their religions but they must pay jizya.(religious tax)
