20/20: Pastor to Power: Billy Graham and the Presidents

He has preached to more people on more continents than anyone in the history of the planet. He's provided spiritual guidance to hundreds of millions and is one of the most revered religious figures of modern times. Reverend Billy Graham, the world's most famous evangelist, has also ministered privately to the world's most powerful men: the presidents of the United States. Charles Gibson explores the untold story of Billy Graham's ties to eleven U.S. administrations - from Harry Truman to George W. Bush.