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Income tax benefit (expense) OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax Income tax benefit (expense) OCI, Foreign Currency Transaction and Translation Gain (Loss), Arising During Period, Tax Change in performance bond and guaranty fund contributions Change in performance bond and guaranty fund contributions Change in performance bond and guaranty fund contributions Entity Filer Category Entity Filer Category Nonrecurring fair value [Abstract] Nonrecurring fair value [Abstract] Nonrecurring fair value [Abstract] Income Statement Location [Domain] Statement of Income Location, Balance [Domain] Purchases of available-for-sale marketable securities Payments to Acquire Debt Securities, Available-for-Sale