At their meeting last week, Stephenson said he did not talk about the merger with Donald Trump, who expressed opposition to the deal during the campaign.
AT&T's proposed $85 billion purchase of media content powerhouse Time Warner is a "basic vertical merger," Stephenson said on "Squawk Box" from the sidelines of the World Economic Forum in Davos, Switzerland.
Speculation that AT&T might need to spin off CNN to get the deal through regulators would not be relevant, Stephenson argued, saying such a move would not serve to reduce competition.
"I don't know why we'd even talk about that," he said. "It doesn't seem relevant to approving a deal like this. What would be the competitive issue that you're remedying with spinning off CNN? There are not competitive issues with owning CNN."
Time Warner boasts an entertainment portfolio of television networks, including CNN, HBO, TBS and TNT, as well as the Warner Bros. film studio.
AT&T, which in 2015 bought satellite television service DirecTV for $48.5 billion, launched late last year DirecTV Now, the company's skinny bundle of channels delivered over the internet.
As for last week's meeting with Trump, Stephenson said the president-elect and he did discuss tax reform, specifically proposals to lower corporate taxes for American corporations.
AT&T would consider increasing capital investment, for such initiatives like fifth-generation wireless technology and laying more fiber cable, if Trump and Republican leaders on Capitol Hill were to lower business taxes, Stephenson said.
"We spent over the last five years $140 billion" in the United States, he said. "We probably would step our capital spending up."
Another area of discuss with Trump was business regulations, Stephenson said.
"[Trump] asked me straight up, 'Has this regulatory environment been difficult for you guys.' And I said it's had a huge impact on how we think of investment in the U.S.," said Stephenson. "We talked about what the implications of what streamlining regulation would be."