Here at StreetAuthority, we like to keep tabs on where the richest people in the world are putting their money.

After all, billionaires such as Warren Buffett are some of the smartest investors on the planet (Berkshire Hathaway’s (NYSE: BRK-B) 20% average annual gain in book value since 1965 attests to that).

They also have advantages the rest of us don’t: Entire staffs of MBAs working for them… Wall Street CEOs who give them sweetheart deals to get their business… and friends at the highest levels of government and society who can steer them toward the next big thing.

So it never hurts to look at what stocks investors like Buffet are buying…

And after looking at Berkshire Hathaway’s most recent filing, I must say there is one stock (at least) that Buffett and I seem to agree on: ConocoPhillips (NYSE: COP).

With a position totaling 29 million shares (worth roughly $2 billion), ConocoPhillips is Berkshire Hathaway’s largest energy holding.

Berskhire Hathaway started acquiring the shares in 2006, with a cost basis close to $70 a share. Today, the shares trade closer to $69, meaning you can actually buy Buffett’s favorite energy stock for less than he did.

But is it a still good buy? After all, a lot has happened since 2006 — especially in the energy sector.

Simple answer, I believe it is. In fact, I’m such a believer that I recently bought shares of COP to add to my “real money” portfolio for my premium advisory, Energy & Income.

Here’s why…

You might have seen ConocoPhillips in the headlines recently. The company has created a lot of buzz in the energy sector with its recent break-up announcement. (I actually covered the announcement in detail in my latest issue of Energy and Income.)

But if you aren’t familiar with the story, here’s what you need to know…

In the first half of next year, ConocoPhillips plans to separate into two different companies. One company will consist of its exploration and production (E&P) unit, while the other will be dedicated to its refining and marketing businesses.

Under the current plan, investors will receive one share in the new refining firm for every two shares they currently own in the company.

After the split, Conoco will become the nation’s largest pure-play exploration and production company. Its operations span 17 countries around the globe, and its wells bring 1.5 million barrels of oil to the surface each and every day — with 8.5 billion waiting in reserve.

Phillips 66, the new refining company, won’t exactly be left empty-handed either. The new organization will retain control of everything else, a valuable collection of midstream, downstream and chemicals businesses. The company will have refining capacity of 2.2 million barrels per day and affiliations with 7,500 branded retail outlets.

I like this move for a couple of reasons. For one, with each company acting independently, they’ll be better positioned to focus on their individual business strategies.

It also frees up more cash for the exploration and production unit — a move that will allow management to allocate more money to finding and developing new oil fields.

Specifically, ConocoPhillips has earmarked $15.5 billion in capital expenditures for the upcoming year — 90% of which will be dedicated to growth projects to help stimulate oil and gas production.

Much of that will be invested overseas, most notably on a major liquefied natural gas (LNG) venture in Australia. But the lion’s share will stay in North America, where the company is taking aim on high-return shale plays such as the Bakken and Eagle Ford formations.

As these upstream investments take root, Conoco’s oil production in the lower 48 states alone is expected to rise by 50% (from 400,000 barrels a day to 600,000) through 2015 — at higher margins per barrel.

These sales (along with continued divestitures of noncore assets) will pave the way for massive stock buybacks. ConocoPhillips has repurchased 155 million shares this year and retired more than 15% of its total outstanding shares since 2010.

Now, management is promising to fund another $10 billion in repurchases during the next couple years, which could take as much as 10% of shares outstanding off the market.

This means profits (and dividend distributions) will soon stretch much further on a per-share basis.

Action to Take –> With all this in mind, this is one stock Warren Buffett and I agree on. And right now you can own the shares for less than he paid.

P.S. — When ConocoPhillips splits in two, I think the stock can really take off. It’s already in an absolute sweet-spot for investors. Why? Because it belongs to a select group of stocks that make up 57% of the 21 best performing income stocks of the past decade. For more information, or to see the full list of 21 stocks, visit this link.