HIDs are High Intensity Discharge lights. As has already been mentioned, projectors are the best housing for them because they have a defined cutoff; if you have stock projectors in your Durango then when you turn your brights on it is really the same light, but it raises the cutoff. Many Mopars now come with projector housings but AFAIK they are all halogen projectors.
Some idiots fit HIDs into the stock halogen housings that came on their vehicle so the lights glare into oncoming traffic really bad and make it hard for other drivers to see. This can cause accidents and cops will often ticket these people. People also do this with LEDs, but LEDs don't actually cast their beam as far as halogens without a properly designed, LED specific housing; so while it looks really bright up close, your range is reduced and you also blind oncoming traffic. Some people fail to realize that many incandescent bulbs are actually directional, and the location of the filament within the reflector housing is important so you can't just drop in some LEDs on a plastic stick and have them work properly in a halogen housing. The high end F-150s have LED headlights in properly designed housings (though people still complain about them) and so do some Acuras and maybe some Hondas now too
If you do have projectors you can safely drop in LEDs or HIDs; and though HIDs are more complicated to set up they perform better in this application.