The IMF GFSR has a nice table (p. 10) showing the estimates of global bank writedowns by domicile in billions of U.S. dollars. In bar charts (full bar = estimated holdings, red = estimated writedowns):

Message: Euro area banks are bigger and smarter, no? But they will probably have to raise more capital.

(Foreign exposures of regional banking systems are based on BIS data on foreign claims. The same country proportions are assumed for both bank holdings of loans and securities. For each banking system, the proportion of exposure to domestic credit categories is asumed to apply to the overall stock of foreign exposure.)