How long until Winnie-the-Pooh is public domain?

Excuse me, but I was wondering if you could clarify something for me. I've been hearing a lot about the concept of public domain lately, and I'm particularly interested in knowing when the beloved character Winnie-the-Pooh will fall into this category. Could you perhaps provide me with an estimate or an explanation of the process behind determining when a work like this becomes public domain? I'm quite curious about the legal intricacies surrounding such matters.