The firm, to be run by current CFO Michael Angelakis, plans to invest in, and help run, “growth oriented companies” in the U.S. and abroad, Comcast says this morning. The cable and broadband colossus will put up $4 billion of its capital — and be the sole outside investor for 10 years.

“This is a time of tremendous change and opportunity in our core technology and media industries, as well as in adjacent business areas,” CEO Brian Roberts says. “We believe the ability to establish entrepreneurial ventures that partner with and participate in the growth of innovative companies can be an important driver of strategic and financial value creation for our company.”

Comcast says it has begun looking for a new CFO, although Angelakis will continue to serve as a Senior Advisor — and help with “the integration process for the Time Warner Cable and related transactions.” He has put at least $40 million into the new fund  and will control as much as 40% of its economic interests for the first five years, and as much as one-third during the remaining five years, Comcast says in an SEC filing. He’ll make $8 million a year in his new job, as well as $100,000 from Comcast for his Senior Advisor role.

Comcast can back out of the deal if Angelakis is no longer the firm’s CEO. It will pay an annual $40 million management fee, “subject to certain offsets.” It has the right to approve “certain proposed investments” and will have first dibs on the investment company’s assets. Comcast also will provide administrative services “on arm’s-length terms” and consolidate its financial results with its reports.

Additional cash for the fund will come from “other senior members of the new company’s management team.” They will own non-voting preferred shares.

Angelakis joined Comcast in 2007 from private equity firm Providence Equity Partners, where he was Managing Director and a member of the Management and Investment Committees. In addition to his Comcast duties, he’s Deputy Chairman of the Federal Reserve Bank of Philadelphia.

“As we enter the final phase of the Time Warner Cable transaction, this is a great time to begin a transition and I am excited to start this new, entrepreneurial company,” he says.