Am I right to think close friends should share everything?

Am I right in thinking that when two people are extremely close friends, they're supposed to share almost everything with each other – deep vulnerabilities, insecurities, quirks, personal history (including everything that happened before they became friends, so it feels as though they've known each other from the very beginning), and other private aspects of their lives? I also feel that close friends should keep each other updated about their day-to-day lives and regularly share what's going on with them.

I did get this type of connection from my partner, but I also wanted a platonic same gender friend on this. Is it too idealistic or realistic?