Additionally, Bungie confirmed that one's Guardian character is playable across both the current generation (PlayStation 4 or Xbox One) and past generation (PlayStation 3 or Xbox 360), within the same system.
Bungie's David Shaw said this was planned all along. "Our service is built with flexibility in mind," he said. "As a player of Destiny, you have a Bungie account that's bound to your PSN ID or your Xbox LIVE Gamertag, instead of a specific generation of device." That's only for character availability; cross-platform play of any type isn't supported.