$18 billion. Profit. One quarter. Pure insanity.

How insane? It’s the highest earnings for a company in a quarter… ever. And it sets Apple up to post the most earnings for a company in a year… ever.

With this latest quarter, Apple surpassed ExxonMobil in 2008, Royal Dutch Shell in 2008, and Gazprom in 2011 for the most profitable quarter in the history of business. The unifying theme? All oil & gas companies. All operating in a world before the recent collapse of oil prices. Hence the joke: Gazprom to start selling smartphones. It’s funny because it should be true.

Forget Apple going bankrupt. Forget the iPod being silly. Forget the Apple Stores never working. Forget the iPhone going nowhere. Forget the notion that Apple won’t make it without Steve Jobs. Forget the calls to fire Tim Cook. Apple now sits firmly atop the business world with no peers.

In fact, Apple now has the best problem in the world: having unearthed the best business in history, the iPhone, there are seemingly few places left to dig for gold — or, perhaps more appropriately, oil.

“There’s a whole ocean of oil under our feet! No one can get at it except for me!” — Daniel Plainview, There Will Be Blood

I’ve long held that the iPhone is such an insanely good business for Apple (not only now bigger than all of Microsoft, it may well be bigger than any other business out there by itself) that they’d have a seemingly impossible time replicating it and continuing to grow.

Apple has skirted the “law of large numbers” by continuing to grow the iPhone business. And there’s undoubtedly still more room for growth — especially in places like China. But what about other products?

The iPad, while massively successful in its own right, pales in comparison to the iPhone. The Apple Watch is likely to “suffer” the same fate. A television product? It may mean a few billion extra dollars to Apple, but that’s nothing compared to iPhone.

So the question is: where does Apple go from here? My old joke was that they’d have to become an oil company. It’s not so funny anymore.

Maybe a car company? Or a bank?

Apple Pay is a first step in the direction of the latter. But at least right now, the business seems to exist to sell iPhones. Of course, that’s how the App Store started as well, and it just keeps growing and growing and growing. Apple Pay will probably be the same.

2015 may not be the year of Apple Pay. But 2016 may be.

The iPhone will eventually fade as all businesses do. But as Apple proved with the iPod, they know how to use a phenomenon to fuel the search for the next one. The iPhone may give them a decade to do that. Maybe longer.

But again, the bar is now just set so high. What on Earth can be a bigger business than the iPhone? It’s impossible to come up with something right now because it seemingly doesn’t yet exist. It’s not cars. It’s not banking. It’s not even oil. It will have to be invented.

Or it’s possible that it does exist right now and it’s a market waiting for the catalyst that the iPhone was for smartphones. And it’s fun to think about what it could be. But it’s impossible to know. Even Apple didn’t know how big the iPhone business would become.

The biggest business ever.