[The Electrician]

The film has made more than $100 million, the highest ever for a documentary

Calling it a "documentary" film is Orwellian at best. Merriam-Webster defines documentary as "FACTUAL, OBJECTIVE ", however no intellectually honest person would claim that Moore's film is either. "Political comedy" or "political commentary" or "polemic" would be a more accurate description.

[weegee]

I'll bet if you adjust for inflation (as Box Office Mojo does for tracking the all time biggest hits), you will probably find some other documentaries that did better at the box office.

Early in the hype for this film, they excluded IMAX films from their boasting as well as concert films. When you go ahead and exclude all of the documentaries that are not works of fiction, the competition becomes much easier.