https://techcrunch.com/2018/05/19/apple-started-paying-15-billion-european-tax-fine/

It took a couple of years, but Apple has started to pay back illegal tax benefits to the Irish government. The company has paid $1.77 billion (€1.5 billion) into an escrow account designed to hold the fine. Apple has to pay $15 billion in total (€13 billion).

In August 2016, the European Commission said that Apple benefited from illegal tax benefits in Ireland from 2003 to 2014. According to Competition Commissioner Margrethe Vestager, Apple managed to lower its effective corporate tax rate thanks to a Double Irish structure.