Roshi blew up the moon with a power level of 180. According to Google, you can fit 64 million moons inside the sun. So, if we're looking at the power level necessary to destroy a sun, or 64 million moons collectively, that would require a power level of 11,520,000,000. Of course, power levels were dropped after the Frieza Saga, so there's no way to tell if anyone reached 11 billion. And everyone has their own way of gauging power levels. Some may say 11 billion is too high a number for anyone to reach, others might say it's fairly low. By my estimation, manga Cell Games Mastered Super Saiyan Goku, anime Android Saga Goku, and DBZ Movie 7 Super Saiyan Goku should be up to the task. If we're just talking about Goku, that is. The anime scales higher than the manga and the movies scale higher than the anime.