Batman: The Dark Knight Returns (Animated) - Voice Casting Announced

Variety has an article containing the announced voice casting:

Peter Weller (Robocop) will star as Batman/Bruce Wayne and Modern Family’s middle child Ariel Winter will play Robin. 

Also in the cast are David Selby, the veteran actor who starred in the original Dark Shadows soap opera as well as the classic 1980s soap Falcon Crest; Wade Williams (Prison Break) as Harvey Dent/Two-Face; and Michael McKean as Dr. Wolper, the psychiatrist who releases the Joker from the insane asylum.