Not really, just 2850mAh. That's smaller than the G2/G3, Note 3/4, and a few other flagships. It's definitely a large battery, but I wouldn't say ginormous.I will not sell my 6+ for that thing, I'll keep it as well and have my cake and the icing.
That is if all the rumors about the M9 come to fruition. I'm concerned about the weight mostly though, it is rumored to have a ginormous battery but I guess battery life will be more important to most.