"The pension funded status of the nation's largest corporate sponsors reversed direction in 2014, dropping nine percentage points as falling interest rates (which increased liabilities) and the impact of new mortality tables were only partially offset by strong returns on pension plan assets ... [A]ggregate pension funded status is estimated to be 80% at the end of 2014, a decline from 89% at the end of 2013.... [T]he pension deficit increased to $343 billion at the end of 2014, more than twice the deficit at the end of 2013, as overall pension plan funding weakened by $181 billion last year."