While looking for a wireless mouse I am surprised how hard it is to find security information on them (I guess most consumers simply don't care). I managed to find some information about security in Logitech devices. Is there any similar information about Microsoft mice I failed to find?
I could not find a general document like the one you posted, but this Google search shows that some models use 128-bit AES encryption. I would use the following search, and add your specific model to the search.
Search "microsoft wireless mouse or keyboard encryption site:microsoft.com" (without the quotes).