Complex sentence: In 2007, he was an Executive Producer of American Idol Gives Back, the most successful television charity event in history, which raised $75 million for a host of organizations working to help those living in extreme poverty in America and in Africa.
Split into simpler sentences: In 2007, he was an Executive Producer of "Idol Gives Back", then the most successful television charity event in history. It raised $75 million for organizations working to help people living in extreme poverty in America and in Africa.