There's a question similar to this, but it asks if you simply can decrypt SSL with the certificate.

So my question is, if you capture all traffic from a device using Wireshark then shouldn't you have at least enough information to decrypt incoming traffic? What I've heard is that the server sends a public key which the computer uses to generate a symmetric key to encrypt data which can only be decrypted on the server. But then if everything is encrypted, how does the browser decrypt incoming traffic? And can't that be intercepted, or how how else is the browser going to be able to decrypt what the server sends?

I also used Fiddler and it seems that Fiddler can read https traffic when I'm on facebook and stuff, so how does that exactly work then?