Dexron ATF will do it. Some ATF types have stuff in it to modify how the clutches hold and are bad for steering systems (add friction-hard steering) I used to could tell you what we paid for that $11 a qt stuff off the bulk tanker truck, but I don't remember.
While you can use ATF (I do) the major manufacturers advise using the "special stuff". They claim that the ATF is less viscous (thicker) and will make the steering a bit harder to respond to the helm.