Federal Reserve Chairman Jerome H. Powell probably will kick off his post-meeting news conference on Wednesday the same way he’s begun every one this year. The Fed, he’ll tell reporters, has “one overarching goal: to sustain the economic expansion.”

Behind that anodyne mission statement lies a grand ambition. Powell is effectively taking on a task that many of his inflation-wary predecessors shunned: extend the fruits of a growing economy to those who rarely benefit, from struggling African American families to poor rural white people.