When oil prices tank, most energy companies pull back. ExxonMobil -- a dividend aristocrat -- did the opposite. The Texas-based oil giant wrapped up $20 billion in share repurchases last year while crude posted its steepest annual drop since the pandemic. That aggressive buyback program retired shares equivalent to roughly a third of those issued in the Pioneer Natural Resources acquisition. It's a move that signals confidence few rivals can match right now. Exxon (XOM) CEO Darren Woods made that clear ...