Update: Square Enix has just announced that both Final Fantasy 15 and Kingdom Hearts 3 will also be released on Xbox One.
Original story: Final Fantasy Versus 13 is now Final Fantasy 15 and has been confirmed for release on PS4.
The game's name change was announced during Sony's E3 Media Briefing.
Square Enix also announced that Kingdom Hearts 3 is in development for PS4, again without mentioning an exclusive.
Presumably both titles will also be on Xbox One.
PS4 and PS3 are, however, getting a Final Fantasy exclusive, with the release of Final Fantasy 14.