The Austrian school system used to not have undergraduates. So when graduated from a high school, you just got in a Master's program for about 2 years and then PhD program for about 4 years. However, we called it "Master" and "PhD". So it means that "it is a PhD degree in Austria", but by American standards, it is actually "a Master's degree". Should I still list as "PhD" degree on my CV?
I would argue the opposite way. An Austrian PhD definitely qualifies as PhD internationally. The former master curricula were typically composed of two parts that resemble the undergrad and graduate master studies. So in essence, in order to get an Austrian PhD, you need to pass undergraduate, graduate master and a PhD curriculum, while in American standards, you just need an undergrad + a PhD program. I don't see, why this should be worth less. Besides, the PhD curriculum is distinct from the others in both cases since it typically involves research, publications and conference or workshop presentations. So a PhD degree in one country also matches a PhD degree in another just by the competence you gained in addition to exams.
I don't have the exact comparison in terms of credit/effort or something like that. Maybe someone else can clarify.
Before Bachelor and master was introduced at Austrian universities, the first degree a student could get was a Magister- or Diplomgrad (master- or diploma-degree). The titles broadly fall in three categories:
Magister/Magistra is awarded for studies in natural sciences (Mag.rer.nat), pharmaceutics (Mag.pharm.), law (Mag.iur.), theology (Mag.theol.) and so on. These studies typically last 8 to 10 semesters.
Diplom-Ingenieur/Diplom-Ingenieurin (Dipl.-Ing.) is the degree for technical sciences. These studies typically last 10 semesters.
Doktor der Heilkunde (Dr.med.univ.) is actually the master degree for a medical doctor. This one has a strange naming, because it is not a doctors degree. Confusingly, a veterinarian finishes with Mag.med.vet. Medicine typically has to be studied for 12 semesters.
Although the titles have different names depending on the type of university and the type of studies, these are all considered the second highest degrees in Austria. The English translation would be---depending on the studies---one of master of art (MA), master of law (LLM), master of science (Msc), medical doctor (MD) and so on.
Having one of the degrees above is usually a requirement for starting PhD studies. PhD studies end with a doctor degree (Doktor of something). So there is Dr.rer.nat., Dr.iur., Dr.theol., Dr.techn. (following a Dipl.-Ing.), Dr.med.vet., and Dr.med.univ. et scient.med. (this one is the true doctor degree in medicine). Those are commonly translated as PhD.
When the bachelor-master-system was introduced at my university, they would simply split the studies into two parts. After 6 semester, one would get the bachelor degree and after 4 more semesters they would get the Magister/Diplom (master). Having only a bachelor is not enough for starting a PhD.
There is another type of university in Austria called Fachhochschule (Universities of Applied Science). Their studies end with a Mag.(FH) or Dipl.-Ing.(FH) after 8 semesters. These universities are not allowed to offer PhD studies. However, having such a degree allows to start a PhD at a 'regular' university but one has to attend additional courses (often for 2 semesters).
The Austrian Ministry of Education has published the degrees and their international equivalent (pdf).