If you are in the kind of adversarial management relationship where this is necessary, you have already lost.
Do you think this kind of guy, when you point to "hey remember the conversation, here's the follow-up mail with the meeting notes" he's gonna be like "oh yeah, I was wrong, you are right." ?
It's good to have meeting agendas and follow up minutes, I just rarely find that they are going to help you litigate anything. More to remind you how a decision came to be.