Worldwide Income
  
Worldwide income isn’t the income of the whole world. Rather, it’s “worldwide income” in the context of the US.
Worldwide income refers to all of Americans’ taxpayer income, at home and abroad.
If you’re a US citizen or resident alien of the US, the IRS demands to know about your “worldwide income,” which is any income you have anywhere in the world, whether it’s taxable or not. People who hide their money in offshore accounts are likely doing so to hide some money, and lie about their worldwide income to the IRS, which is a big no-no, but can save them a lot of money if they get away with it (think: the Panama Papers).