Questions on Hearts of Iron 3

So, I was wondering who owns Hearts of Iron 3?? I am looking at picking it up on Steam should it go on sale. It to me looks like a much more in depth game of say Axis and Allies which I would like. I have Civ 5 and quite enjoyed it for a bit but it is a bit of a different beast, so before I purchase I would like some good information on it besides what I have just only read. Thanks for the help in advance!