This[1] seems to indicate viewership of the halftime show peaked at 140M.
1: https://web.archive.org/web/20090412054158/http://www.suntim...
1: https://web.archive.org/web/20090412054158/http://www.suntim...
a hundred million people in one venue is certainly an unbelievable number though.
[1] http://www.maxim.com/entertainment/prince-2007-super-bowl-pe...