PHILADELPHIA — Comcast announced this morning it plans to buy a majority stake in NBC Universal for $13.75 billion, giving the nation's largest cable TV operator control of the Peacock network, an array of cable channels and a major movie studio.

Although the deal could mean that movies could reach cable more quickly after showing in theaters, and that TV shows could appear faster on cell phones and other devices, it was already raising concerns that Comcast would wield too much power over entertainment.

Indeed, if the deal clears regulatory and other hurdles, Comcast would rival the heft of Walt Disney — which Comcast CEO Brian Roberts already tried to buy.

Comcast, which already serves a quarter of all U.S. households that pay for TV, would gain control of the NBC broadcast network, the Spanish-language Telemundo and about two dozen cable channels, including USA, Syfy and The Weather Channel. It also would get regional sports networks, Universal Pictures and theme parks.

In agreeing to buy 51 percent of NBC Universal from General Electric, which has controlled NBC since 1986, Comcast hopes to succeed in marrying distribution and content in a way Time Warner could not. AOL and Time Warner are undoing their ill-fated marriage Dec. 9. Time Warner has already shed its cable TV operations.