I've been dating someone at work for a couple years. Same company but very different areas, we barely come across each other daily and don't intersect work-wise. Is it a good idea? Probably not. But it's a much better idea than dating someone you actually deal with at work on a frequent basis. People know, obviously. The initial gossip, rumors etc were dicey but once it just became old official news nobody cared. My bosses know and don't care either.
Truth be told, a lot of people date and marry someone from work. If you're going to do it you have to understand the risk and be willing to prepare for how to save your ass. That means if you're one of the a$$holes who regularly cheats on your girl...do not cheat while dating someone at work. Because when shyt hits the fan it will impact work life and you will get fired. Likewise if she cheats on you...you better either get a new job or take that shyt on the chin because when shyt hits the fan it will impact work life and you will get fired lol. You basically have to decide that no matter how things turn out you will move on afterwards with no hard feelings or any hint of problems.