Not just that. Once the income has been taxed outside the US, it can no longer be taxed by the US.
And so far, the US Treasury considered this income as "not taxed", meaning it would have been taxed at the corporate US tax rate when and if moved to the US.
Which is why Apple hasn't moved that money to the US, and has something like $190 billion sitting outside the US.
So the treasury is being extremely disingenuous here, they just want to be the ones to tax this income.