Which is the amount they couldn't find a way to avoid. Their profits would be taxed at around 40% in the US, but they funnel them to Ireland (the famous "Double Irish") and pay 0% on them. What they do pay is made up of sales tax, employment taxes, and tax on things like property that they can't pretend does not exist in any taxable jurisdiction.
This is somewhat misleading. The US is special in that its the only country that actually taxes income that isn't even earned in the country. Most countries will tax someone on the income generated in the country, but not tax income generated outside the country. That includes both corporations and *people*. If you are a US citizen and you go outside the country and earn income, you're required to pay US income tax on that income, even though it was earned entirely outside the country. To repeat: that's something practically unique to the US.
The US does provide an exception: if that income was already taxed by another country, you're allowed to declare that because you already paid taxes on that money to someone else, you don't have to *also* pay taxes to the US. Again: that's not just for corporations like Apple, but also for individuals.
Apple is required to, and does pay US income taxes on net income it earns in the US: it cannot simply "funnel" the income to another country to dodge taxes, and everyone saying that simply is confused or mistaken. If that was possible every corporation would do it and no one would pay any taxes. What companies like Apple *can* do, however, is a) pay taxes on that income in another country, particularly one with a much lower tax rate and b) don't bring the money back to the US, where they would then have to pay US tax on it.
Is this "dodging taxes?" Yes. But not really *US* taxes. The countries with the biggest beef with Apple are really European countries for whom Apple doesn't pay taxes on income generated in those countries because that revenue is funneled into Ireland. But that money would *not* be "taxed at around 40% in the US" because if Apple didn't funnel that income to Ireland (where it has special sweetheart deals that Ireland gave to many companies, to the chagrin of many other EU countries), it would then be taxed in the individual countries it was earned, and the US would still not see a dime of it.
As to dodging taxes by not explicitly transferring that money earned overseas back to the US? It has yet to be explained why a company that earns money overseas has an obligation to transfer that money to the US explicitly for the sole purpose of paying US taxes on it, and for no other reason. That's simply illogical.
But as to the income Apple generates in the US by its business operations in the US: for the most part, it pays taxes on that income just like every other corporation.