Good Day Jangaplanet
If I were worth a billion dollars I would start by ACTUALLY paying my fair share of taxes. As you know, rich people have all kinds of ways to dodge taxes, using offshore tax havens, bringing the money back into the country through convoluted means which actually disguises the money as untaxable "loans." One such operation pioneered in the 1970s in the United States was something called the "Dutch Sandwich."
Multimillionaire movie actos (and I suppose television actors as well) and big name musicians do this. I mention this because I think that one reason some celebrities do so much charity work is guilt over not paying their taxes, ironically enough.
But they probably tell themselves that they have to dodge their taxes because they can "do so much more" by holding onto their money. In time they may grow to be hostile to the government, becoming economically libertarian or downright reactionary.
Have you ever noticed that when someone owes you money and he can't pay it back (or doesn't want to pay it back), actually beomes hostile toward you (the one he owes)?
Anyway, I would start by paying my taxes to the federal, state, and local government -- which has more impact on more people, more deeply than giving to "charity." Government can do things that private individuals or foundations or charities simply cannot do.
Take it easy.