Working with Animations > Editing Animations > Duplicating and Copying Keys
  
Duplicating and Copying Keys
Use the Duplicate command to create an identical key that appears on top of the original. After you perform the Duplicate operation, the new key is automatically selected, and you can drag it to a new location. Use the Copy command to create a copy of the key on the clipboard. Then, paste it in a new location on the timeline, or paste it in another animation.