Maybe some elaboration is in order, then? :)

Abstract:

The 2007-09 financial crisis was associated with a huge loss of economic output and financial wealth, psychological consequences and skill atrophy from extended unemployment, an increase in government intervention, and other significant costs. Assuming the financial crisis is to blame for these associated ills, an estimate of its cost is needed to weigh against the cost of policies intended to prevent similar episodes. We conservatively estimate that 40 to 90 percent of one year's output ($6 trillion to $14 trillion, the equivalent of $50,000 to $120,000 for every U.S. household) was foregone due to the 2007-09 recession. We also provide several alternative measures of lost consumption, national trauma, and other negative consequences of the worst recession since the 1930s. This more comprehensive evaluation of factors suggests that what the U.S. gave up as a result of the crisis is likely greater than the value of one year's output [$15 trillion].

Excerpts:

Better Markets Inc. (2011) estimated the cost of the crisis at $12.8 trillion, counting the output that was lost and the output that would have been lost if not for extraordinary fiscal and monetary interventions. However, we do not consider avoided output loss a cost of the crisis because this ìlossîwas not actually realized. Given how we define the costs of the crisis, the benefits of the extraordinary policy response are already factored into the output loss calculation.

The Government Accountability Office (GAO 2013) reviewed the literature on the cost of previous financial crises and determined that the costs associated with the most recent recession should likely fall within the range of a few trillion dollars to more than $10 trillion. Although the costs of past crises guide our estimates, we are primarily concerned with the cost of this specific crisis. We believe that the five years of data since the beginning of the recession, and a forecast of the return to trend, provide enough information to form a more accurate estimate than an average of past crises that have diverse, situation-specific factors at play.

Boyd and Heitz (2012) find $7.3 trillion to be the lowest conceivable crisis cost estimate using similar methodology to this study. We employ slightly different assumptions about the counterfactual path of GDP and its forecast past 2012 and put less emphasis on arriving at a lower bound, remaining careful not to overstate the costs.

https://dallasfed.org/assets/documents/research/staff/staff1301.pdf