We consider some well-known families of two-player zero-sum perfect-information stochastic games played on finite directed graphs. Generalizing and unifying results of Liggett and Lippman, Zwick and Paterson, and Chatterjee and Henzinger, we show that the following tasks are polynomial-time (Turing) equivalent. – Solving stochastic parity games, – Solving simple stochastic games, – Solving stochastic terminal-payoff games with payoffs and probabilities given in unary, – Solving stochastic terminal-payoff games with payoffs and probabilities given in binary, – Solving stochastic mean-payoff games with rewards and probabilities given in unary, – Solving stochastic mean-payoff games with rewards and probabilities given in binary, – Solving stochastic discounted-payoff games with discount factor, rewards and probabilities given in binary. It is unknown whether these tasks can be performed in polynomial time. In the above list, “solving” may mean either quantitativ...