Answer:
Generally:

That there is one God
That God created everything
That Jesus was his son
That Jesus died for their sins
That he rose from the dead
That sins may be forgiven
That Jesus will return to Earth
That there will be a final resurrection of all people
That they will be judged, and admitted into heaven, or not.

Many sects have arisen that differ with these ideas, but they were the basic doctrines of the early church.
First answer by Zenballwizard. Last edit by Zenballwizard. Contributor trust: 639 [recommend contributor recommended]. Question popularity: 2 [recommend question].