I've given some money to the scholarships in the District of Columbia, to the best students in D.C... many of the students have written me letters telling me they could not have afforded to go to college without the scholarship and money I've given them.

I am involved in a lot of nonprofits. And when I reached the ripe old age of 60, I wanted to provide leadership to some I had been involved in.

I realised how rich I had become and I asked myself, 'Do I really want to be the richest person in the cemetery?

I'm on a lot of nonprofit boards, but if I didn't enjoy it I wouldn't do it. I haven't yet done anything that's transformational in philanthropy. But I hope at some point to target two or three causes or organizations and really make transformational gifts.

My work life is intense. But I love what I do.

I give away about 50 percent of my income, so my, you know, desire to give back to the country is pretty strong and I intend to give away a lot more. I've signed the giving pledge with Warren Buffett and Bill Gates, and I intend to give away the bulk of my money.

I think it's a little unfair for people to say you're not paying your fair share of taxes. I'm paying what I'm supposed to pay. Change the law, and I'll pay what I'm supposed to pay.