What is the difference between Protect and Detect?

Question

In Pokemon, there are two moves. Protect and Detect. On the outside, they seem to be exactly the same, besides PP amounts and move types. Are there any other differences between these two moves, or are they practically clones?

Answer 1

From Bulbapedia:

Detect's technical mechanics, including formulas, glitches, and exceptions, function identically to Protect in all generations.

So yes, they're practically the same move.

The only difference I see, besides PP amount and type as you wrote, is that they have a different behaviour in Contests:

• Protect is a Cute move, it rises Appeal by 1 unit in normal Contests and by 2 units in Constest Spectaculars.

• Detect is a Cool move, it rises Appeal by 2 units in normal Contests and by 1 unit in Constest Spectaculars.

And, of course, Protect has its own technical machine, TM17.
Detect has none.

Answer 2

Not only are they clones in functionally every way right now, they also run off the same counter, so using Protect or Detect will also cause the other to have a chance to fail on the following turn.

If we ever see some ability that specifically affects Normal or Fighting-type moves, they might behave differently, but not right now.