"We are excited about the merger," Roberts told Wall Street analysts during a conference call to discuss earnings. "Our integration planning is on schedule as we continue to work toward regulatory approval."
Competitors also fear that Comcast, which would become the nation's dominant Internet and cable TV provider if the deal is completed, would unilaterally set programming prices for the entire industry.
Under the deal, Comcast would have about 29 million cable TV subscribers, with about 1.8 million in the Los Angeles region.
The Justice Department is investigating whether a bigger Comcast would pose a threat to competition. Separately, the FCC is weighing whether a merger of the nation's two largest cable companies would serve the public interest.
The FCC is scheduled to make a decision by the end of March.
"These two companies are forging ahead with this," Wells Fargo Securities media analyst Marci Ryvicker said in a research report Tuesday.
Comcast shares opened up more than $1, to $59 a share, even though the giant Philadelphia-based company's fourth-quarter earnings missed Wall Street's forecasts.
Investors seemed pleased that Comcast reported slightly higher earnings and raised its dividend 11%, to $1 per share on an annualized basis.
The company also said it would spend $4.25 billion this year buying back shares.
For the quarter ended Dec. 31, Comcast earned a profit of $1.93 billion, or 74 cents a share, compared with $1.91 billion, or 72 cents a share, in the year-earlier period.
Excluding some items, earnings came in at 77 cents a share while Wall Street analysts had estimated 78 cents a share.
Revenue rose 4.8% to $17.7 billion.
Analysts have been closely monitoring Comcast's subscriber counts, which provide a barometer on the health of the cable and broadband Internet service industries.
Comcast signed up 6,000 new cable TV subscribers in the fourth quarter, although that was significantly less than the year-earlier period. The company added 375,000 high-speed Internet customers during the fourth quarter.
For the full year, Comcast added 1 million high-speed Internet service customers. However, it lost 194,000 video subscribers in 2014 as customers cut the cable cord or switched to another pay-TV provider.
The number represents an improvement from 2013, when Comcast shed 267,000 video subscribers.
Comcast said 2014 marked its best retention in seven years.
If current trends hold, high-speed Internet customers soon should surpass the number of cable TV subscribers served by Comcast.
Federal and state government reviews of the Time Warner Cable deal have focused on the Internet service market because more consumers are getting their entertainment from online sources.