Welcome to the Power 100 of 2015. We are taking a new approach to our annual list of the region's most influential business leaders this year: We're rolling out the list in sections of 25 and grouping our honorees into four categories. Today we unveil the region's Heavy Hitters, those executives who lead the most powerful organizations in town, be it for their size, their reputations or the sheer dollars they generate. Each Monday in October, we'll introduce a new category.