XML 36 R35.htm IDEA: XBRL DOCUMENT v2.4.1.9
Settlement Guarantee Management - Additional Information (Detail) (USD $)
Dec. 31, 2014
Sep. 30, 2014
Settlement Guarantee Management [Abstract]    
Estimated maximum settlement exposure $ 57,600,000,000v_EstimatedMaximumSettlementExposure $ 56,900,000,000v_EstimatedMaximumSettlementExposure
Covered settlement exposure 2,900,000,000v_CoveredSettlementExposure 3,200,000,000v_CoveredSettlementExposure
Estimated probability-weighted value of the guarantee $ 2,000,000v_EstimatedProbabilityWeightedValueOfGuarantee $ 2,000,000v_EstimatedProbabilityWeightedValueOfGuarantee