Lumen Technologies, the successor of Qwest Communications International and owner of CenturyLink, has reached an agreement to sell its consumer fiber business, called Quantum Fiber, to AT&T for $5.75 billion in cash, the two companies announced Wednesday.

AT&T says its acquisition of Lumen, previously known as CenturyLink, will allow it to “significantly expand” its fiber internet service across major cities, like Denver, Las Vegas, Orlando, and others.