According to AdAge, a leaked internal document from Google has revealed that a number of bigwig companies individually spent more than $1 million in the month of June, for buying as in Google’s search results.

Providing a peek into the value of search-related ads of different companies, the document revealed that Apple, as well as chip giant Intel, spent in the neighborhood of $1 million on Google’s AdWords during the month.

The June list of the biggest Google ad purchasers was topped by AT&T which, thanks to the release of the high-profile iPhone 4, spent a whopping $8.08 million. In the second spot was Apollo Group, which spent $6.67 million for the month.

The other companies featuring in the ‘top 10’ list of companies spending huge amounts of cash on ads through Google included Expedia, Amazon, eBay, BP, Hotels.com, JC Penney, Living Social and ADT Security.

The biggest jump in AdWords spending came from BP, which spent $3.59 million for the month - leaping from $57,000 a month before the company’s infamous oil spill episode.

Even though Google has refrained from confirming the AdAge figures, multiple sources with “direct knowledge of spending levels” have verified the accuracy of the AdAge data, which shows that while 47 companies spent over $1 million on AdWords in June; 71 other companies spent between $500,000 and $1 million; and yet another 357 companies spent between $100,000 and $500,000.