My dad probably has a pretty good idea about our finances, although not every detail- He and my mom (who has passed away) were both very financially responsible, my dad left his job at 53 or 54, to do less demanding contract work, and quit entirely at 55 when my mom was diagnosed with cancer, never bothered going back. I have no worries about his financial situation, and learned lots growing up about financial planning and being frugal from them both.
Husband and I don't give anyone all our financial information, but are pretty open with individual items, and our friends know that we're pretty financially savvy, so will sometimes ask about things. For example, how much life/disability insurance we carry and the cost, how/why we choose what retirement saving vessels to use. One of our friends is planning a fist baby, and as the wife and I have super similar jobs and benefits, we told them they could have info about what my income on mat. leave looked like, what pension buyback cost, and the life/disability/health insurance options and cost available while on leave, as well as costs for everything baby related, what we now spend on daycare, ect. Which they took us up on :) But we don't really go out of our way to discuss finances with people, as it makes some people uncomfortable, and I probably wouldn't give anyone our entire financial picture