With the deal, AT&T quickly becomes a major video programming delivery player in the U.S. and Latin America, with access to over 70 million U.S. homes and the opportunity to sell wireless services to DirecTV's customer base of which only one-third currently use AT&T's services, said Stephenson.
In the weeks since the possibility of an AT&T purchase of DirectTV was first reported, many who follow the company wondered whether a deal to acquire Dish Network would be the preferred path given that company's sizable wireless spectrum holdings.
Stephenson refuted that notion, however, telling CNBC the DirecTV deal was always the preferred transaction given its "premium content and customer base" and that the regulatory path for a DISH deal, were it to have ever happened, would have been "more difficult."
Read MoreStagnating DirecTV makes little sense for AT&T: Analyst
"Culture matters," said DirecTV CEO Mike White, "and we have more similar cultures" (than DISH and AT&T). When asked whether he had recently spoken with Charlie Ergen, who controls DISH, Mr. White said he had not.
Both men believe the synergies outlined in the deal will be made reality.
"I would not have taken 70 percent of the consideration in AT&T stock if I didn't believe we can deliver on our synergy targets," said Mike White, DirectTV's chief executive.
In commenting on that structure and why AT&T did not use more cash in the deal, Stephenson noted AT&T's plan to spend as much as $9 billion dollars at next year's auction of wireless spectrum currently held by broadcasters and the continued capital needs of a company that spends $21 billion a year on capital expenditures. He said the company has plans to increase its broadband footprint by another 15 million homes.
"We needed to ensure we have the firepower for next year's auction and beyond," said Stephenson.
Whether the companies will be able to try and deliver on those synergies will now be in the regulators' hands as they consider both Comcast's purchase of Time Warner Cable and today's deal between AT&T and DirectTV—a reordering of the video landscape that would seem to set both companies in motion towards more significant competition. (Disclosure: Comcast is the owner of NBCUniversal, the parent company of CNBC and CNBC.com.)
"This is a terrific transaction for all involved: Enhanced choice for consumers, coupled with increased value for both AT&T and DirecTV shareholders—a natural," said investment managers Todd Combs and Ted Weschler of Berkshire Hathaway. Berkshire has been a top shareholder of DirecTV.
—By CNBC's David Faber