Microsoft uses their own SSL stack, both in client and server software. Banks don't use OpenSSL because they require (often by law) for there to be accountability for the purposes of suing. OpenSSL obviously can't provide that, but others such as Microsoft can. It can of course vary by country - but OpenSSL cannot by law be used here at least because it does not fulfil all legal requirements placed on banking institutions.
Google weren't vulnerable when attempts were made after the news broke, but they are also large enough to have their own SSL implementation, which makes particularly much sense since their business is heavily on service/web hosting. Internal custom solutions are not uncommon to handle your own environment.