did you have any idea?
what does that mean? it means did you know that?
who can I use this expression for?

Question

did you have any idea?
what does that mean? it means did you know that?
who can I use this expression  for?

Answer

You are correct. "Did you have any idea that John was married?" means "Did you know that John was married?" 
"Did you have any idea..." is more emphatic while "Did you know..." is a simple question.

Answer

I'm sorry, my English is bad.

"Did you have any idea?" <<

Answer

I don't understand which sentence you are asking about.