If two of the world’s largest powers share a common commitment to autocratic government, autocracy is not dead as an ideology. ~Robert Kagan

That would be interesting, if autocracy were an ideology and not a catch-all term for one-man rule.  Viewed this way, neither Russia nor China is actually an autocracy (Ross has made this argument about China already).  Autocracy implies that there is a sovereign who personally wields power over the entire apparatus of government because all legal and constitutional authority rests with him.  Autocrats are not typically term-limited, since they recognise no law above themselves.  Absolute monarchs might fairly be described as autocrats (Byzantine emperors would sometimes use the title of autokrator to refer to themselves).  Of course, there have not been many truly autocratic regimes for a long time, and today no major power has one. 

Unless Putin disregards the constitution or has his majority in the Duma rewrite the relevant passage, he will leave office after two terms in accordance with the law.  Of course, in addition to his popular support, Putin represents a power structure of the state intelligence services, the military and oligarchs loyal to the Kremlin.  Russia has a democratic authoritarian nationalist regime that is managed by members of the internal state security and military apparatus.  Authoritarian regimes are conventionally conflated with autocratic ones, because both are “non-democratic” in the way that Westerners think of it, but authoritarian regimes very often go out of their way to give the appearance and institutional structure of consultative and/or populist government.  Authoritarians love plebiscites, and they much prefer some formal body to do the dreary work of pushing legislation.  They are almost always in thrall to democratic ideals and make a point of casting themselves as “true” democrats–autocrats not only would feel no need to do this, but would find any concession to democratic principles inherently offensive.  

Russia’s government does not really fit the “autocratic” bill, but then most modern states don’t actually fit this description.  Genuine royal absolutism went the way of the dodo in central Europe in 1848, and disappeared from Russia in 1905-06; the last genuine modern autocracies ruling major powers vanished in the 1908 revolution in the Ottoman Empire and the 1911 Chinese Revolution.