It depends on the context, but it is less common to mean it literally. If someone means it literally, it is usually in response to a specific question about time. And, most likely they would say "it's been one minute" instead of using "a minute."

Yes, "a minute" is usually taken literally. Native English speakers take time *very* seriously. If you don't mean 60 seconds, you may want to use an approximation, such as "a moment", "a while", etc.

This is true at least my part of the U.S.: If you're speaking to someone over, say, the age of 40, "It's been a minute" means it's been exactly 60 seconds. This is kind of an odd thing to point out to people, unless they say, "Tell me when a minute is up." "It's been a minute" as slang for "It's been a long time" is something I associate with Millennials and younger. I hope that helps!

Haha, I would say “it’s been a minute” in frustration to my daughter when I have to ask her more than once to stop using her laptop and she says “just a minute”!! Here, I don’t mean EXACTLY a minute but I do mean a short period of time like a minute. I have heard the term used to mean “a long time” as in: “Oh my goodness, Suzy, I haven’t seen you in so long!” “Yeah, it’s been a minute, hasn’t it!” But it’s not a very common expression in my life. I would probably say… “Yeah, it’s been ages, hasn’t it!” Or “Yeah, it’s been forever, hasn’t it!”