The US telecoms giant from Dallas, Texas is the country's third largest cable provider to date and they are willing to pay $85.4 for Time Warner who owns CNN and HBO.
Though a senate subcommittee will hold a hearing in November, AT&T's chief executive Randall Stephenson trusts regulators will favor the deal.
"The deal would potentially raise significant anti-trust issues, which the subcommittee would carefully examine," said the Republican Senator Mike Lee who chairs the anti-trust subcommittee.
The combination AT&T's distribution network, which embraces 130m mobile phone customers and 25m pay-TV subscribers, with shows from the Warner Brothers film studios and the cable TV channels HBO, the Cartoon Network and CNN would be the major fusion to be announced this year.
Amidst the seemingly amazing mash-ups, there are conflicts between the Republicans and the Democrats.
Republican candidate Donald Trump has said that he would block the merger if he wins, because it was "too much concentration of power in the hands of too few".
Meanwhile, a spokesman for the Democratic presidential candidate Hillary Clinton said "there were a number of questions and concerns about the deal that regulators needed to scrutinise," but added "there's still a lot of information that needs to come out before any conclusions should be reached".
Clinton or Trump the US Justice Department which can approve, block or put conditions on the takeover going through has still the final say.
"It was not a straightforward issue," said Amanda wait a competition lawyer from Hunton & Williams in Washington.
There are two main problems, she said. Firstly, whether AT&T now has an incentive to withhold Game of Thrones from other cable providers. And secondly, whether AT&T will favour its own content over others that it's carrying.
"Is AT&T going to have an incentive to make HBO and other Time Warner channels more visible, more easily accessible on [AT&T's] various service networks and dis-favour, or maybe even hide, the other channels that it's carrying?" Wait said.
But AT&T argued that there was "no competitive harm that is being rendered by putting these two companies together, so any concerns by the regulators, we believe, will be adequately addressed by conditions," said Mr Stephenson.
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