t the time of his death in 1937, John D. Rockefeller was worth an estimated $1.4 billion. Rockefeller was the first man in history to ever accumulate more than $1 billion (nominal dollars) in total wealth.
Rockefeller's $1.4 billion net worth in 1937 was 1/65th of the total GDP of the United States. In 2011, the total GDP of the United States was $15.09 trillion. If somebody currently had 1/65th of the total GDP of the United States, they would have a fortune of over $232 billion.
It's also important to note that Rockefeller gave away over $500 million (nominal dollars) over his lifetime, which helped to significantly shrink his net worth.