It's safe to say salaries at FB, Apple, and Alphabet are normally distributed. Thus, reporting average or median doesn't matter.
The salary distribution graph for a large corporation is likely to look something like this:
http://www.visier.com/wp-content/uploads/2016/05/Graph-showi...
with a very, very, very long tail to the right representing the salaries of the CEO and senior executives. Depending on the corporation, there may be multiple humps ("salaries for Amazon warehouse workers" representing one hump, and "salaries for Amazon programmers" representing another, for example).
It's nothing like a normal curve.
If the data comes from a sample, then it's going to normal, regardless of the underlying distribution. So the mean and median will be approximately the same.