Kudos to David Kocieniewski for offering a clear account of something that often gets confused in accounts of U.S.-based firms (mainly in high tech) keeping foreign profits "offshore" to avoid U.S. corporate income tax—the money isn't literally located abroad in most cases. As he writes, in the case of Apple, "offshore" funds are typically funds owned by an Ireland-based subsidiary of the company. But they're managed by the same Nevada entity that manages the rest of Apple's money, the accountants are in Texas, and the bank is in New York.
And this is not a peculiar Apple practice. The distinction between foreign and domestic cash is an accounting distinction—which subsidiary owns the money—not a geographic one about where the money physically is.
A key political issue is that a lot of these firms want a repatriation holiday or a permanent low rate on repatriating foreign money. You will typically hear a rhetoric employed about wanting to "bring cash off the sidelines" in order to "invest in America." But again, the actual issue here isn't about where the cash is; it's about what you can do with it. The cash can't be used for share buybacks, special dividends, or extra executive pay until it's reassigned from foreign subsidiaries to the main company.