Looks like a Christmas cactus.

Yes, a real Christmas cactus, Schlumbergera x buckleyi. A large, wonderful looking one!

Although called cactus, it's an epiphytic jungle plant, so doesn't much appreciate getting very dry. Like most epiphytes, its' roots need a lot of oxygen to prevent rotting, so a coarse, airy, porous soil mix is better for that than potting soil. Aside from watering, it's a pretty carefree plant. Easily propagated by laying the trimmed pieces on the soil surface of another pot (after allowing the cuts to dry/heal overnight.)