You need to own the stock at the close on December 15th to receive the divi!
One of two divis. First you were the owner of record on December 1 and own the stock at the close on December 15. You will get the divi on December 15.
Second is you are not the owner of record but do own the stock on December 15. You will get a "bill due" divi and receive the divi on December 20. Take a look at the link on post 4700!