Preheat oven to 375°F. Line 3 cookie sheets with parchment paper.
In a large bowl, use an electric mixer to cream together butter and sugars until light and fluffy. Beat in eggs and vanilla.
In a small bowl, combine flour, baking soda, and salt. Mix in to the butter and sugar mixture. If dough is too thick at this point, add in the milk.
Stir in the oats, chocolate chips, and cranberries. Cover dough and refrigerate for 30 minutes.
Shape dough into balls and space evenly apart on cookie sheets. Bake 12-15 minutes or until edges begin to turn a medium-brown color. Remove from oven and let cook 5 minutes on cookie sheet before transferring to a wire cooling rack.
