The Federal Communications Commission voted unanimously to fine each of the 20 CBS-owned television stations $27,500, the maximum penalty for indecency.

The singer's right breast was briefly exposed to millions of viewers.

The fine is the largest against a television broadcaster.

"As countless families gathered around the television to watch one of our nation's most celebrated events, they were rudely greeted with a halftime show stunt more fitting of a burlesque show," said Michael Powell, the commission chairman.

The FCC decided not to fine CBS' more than 200 affiliates, which are not owned by the network's parent, Viacom Inc.

CBS said it has apologized but believes no indecency laws were broken. Furthermore, our investigation proved that no one in our company had any advance knowledge about the incident," the network said.

Jackson was at the end of a racy duet with singer Justin Timberlake when he ripped off a piece of her black leather top, exposing her right breast.

Timberlake blamed a "wardrobe malfunction." CBS was quick to apologize to viewers.

Since the Super Bowl, some networks have been using broadcast delays on live programs.