American Idol:

Season six premiered with the series' highest-rated debut episode and a few of its succeeding episodes rank among the most watched episodes of American Idol. During this time, many television executives begun to regard the show as a programming force unlike any seen before, as its consistent dominance of up to two hours two or three nights a week exceeded the 30- or 60-minute reach of previous hits such as NBC's The Cosby Show. The show was dubbed "the Death Star", and competing networks often rearranged their schedules in order to minimize losses. However, season six also showed a steady decline in viewership over the course of the season. The season finale saw a drop in ratings of 16% from the previous year. Season six was the first season wherein the average results show rated higher than the competition stages (unlike in the previous seasons), and became the second highest-rated of the series after the preceding season.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". Which television network originally aired The Cosby Show?
NBC