In a ABC News "20/20" program interview to be broadcast Friday, Gates also said he did not take "too personally" some criticism of Microsoft's business practices.
"Well, at age 42, I've given at this point a little over $500 million to foundations that are doing some things I really believe in," Gates said in a transcript of the interview, released Thursday. Those foundations are the Gates Library Foundation and the William H. Gates Foundation.
Last September, Turner announced plans to donate $1 billion to U.N. humanitarian agencies over the next 10 years and called on other wealthy people to do the same.
"Well, I think Ted is great. And I'm very glad he has given that billion dollars. Certainly my giving will be in the same league as Ted's, and beyond," said the Microsoft chairman. "But I don't want to set any artificial milestones. During my lifetime, you know, the money will be given away. I believe I have quite a few years left in my life."
Microsoft (MSFT) has been waging a legal war with the Justice Department, which has charged the company with violating a 1995 consent decree aimed at promoting competition in the software industry.
The government has said it was concerned about the competitive practices Microsoft has used in its attempt to increase its share of the market for Web browsers.
Microsoft has been gaining market share against Netscape Communications Corp., another maker of software to access the World Wide Web.
Gates, asked by interviewer Barbara Walters what he thought about being called greedy and arrogant in the media, said: "When you have the level of success we've had, when you have a business as important as this, with this many competitors, you're going to have people saying some nasty things. And so you have to learn a little bit not to take it too personally."
On Thursday, a spokeswoman for Republican Sen. Slade Gorton from the software giant's home state of Washington said the company was being investigated by the Senate Judiciary Committee about "anticompetitive practices."
The spokeswoman said the committee asked Microsoft to provide documents about the way it conducts its business.