2.4.0.82413403 - Disclosure - Fair Value Option - Components of Gain (Loss) on Debt Designated at Fair Value and Related Derivatives (Detail)truefalseIn Millions, unless otherwise specifiedfalse1false USDfalsefalse$D2013Q2http://www.sec.gov/CIK0000354964duration2013-04-01T00:00:002013-06-30T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$D2012Q2http://www.sec.gov/CIK0000354964duration2012-04-01T00:00:002012-06-30T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDfalsefalse$D2013Q2YTDhttp://www.sec.gov/CIK0000354964duration2013-01-01T00:00:002013-06-30T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false USDfalsefalse$D2012Q2YTDhttp://www.sec.gov/CIK0000354964duration2012-01-01T00:00:002012-06-30T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 4hsbcfc_GainLossOnDebtDesignatedAtFairValueAndRelatedDerivativeAbstracthsbcfc_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Mark-to-market on debt designated at fair value :2false 5hsbcfc_MarkToMarketOnDebtDesignatedAtFairValuehsbcfc_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse142000000142USD$falsetruefalse2truefalsefalse3000000030USD$falsetruefalse3truefalsefalse187000000187USD$falsetruefalse4truefalsefalse-370000000-370USD$falsetruefalsexbrli:monetaryItemTypemonetaryMark to market on debt designated at fair value.No definition available.false2Total mark-to-market on debt designated at fair value3false 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5hsbcfc_GainLossOnDebtDesignatedAtFairValueAndRelatedDerivativehsbcfc_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalsetotalLabel1truefalsefalse119000000119USD$falsefalsefalse2truefalsefalse9200000092USD$falsefalsefalse3truefalsefalse135000000135USD$falsefalsefalse4truefalsefalse-304000000-304USD$falsefalsefalsexbrli:monetaryItemTypemonetaryFair value changes on fixed rate debt accounted for under fair value option as well as the fair value changes and realized gains (losses) on the related derivatives associated with debt designated at fair value.No definition available.true2Gain (loss) on debt designated at fair value and related derivatives6false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5false 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5hsbcfc_MarkToMarketOnDebtDesignatedAtFairValuehsbcfc_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse119000000119[1]USD$falsefalsefalse2truefalsefalse1200000012[1]USD$falsefalsefalse3truefalsefalse205000000205[1]USD$falsefalsefalse4truefalsefalse9100000091[1]USD$falsefalsefalsexbrli:monetaryItemTypemonetaryMark to market on debt designated at fair value.No definition available.false2Total mark-to-market on debt designated at fair value9false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse9false USDtruefalse$D2013Q2_us-gaap_DerivativeInstrumentRiskAxis_us-gaap_CreditRiskContractMemberhttp://www.sec.gov/CIK0000354964duration2013-04-01T00:00:002013-06-30T00:00:00falsefalseCredit risk contract [Member]us-gaap_DerivativeInstrumentRiskAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_CreditRiskContractMemberus-gaap_DerivativeInstrumentRiskAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Credit risk contract [Member]10true 4hsbcfc_GainLossOnDebtDesignatedAtFairValueAndRelatedDerivativeAbstracthsbcfc_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Mark-to-market on debt designated at fair value :11false 5hsbcfc_MarkToMarketOnDebtDesignatedAtFairValuehsbcfc_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse2300000023USD$falsetruefalse2truefalsefalse1800000018USD$falsetruefalse3truefalsefalse-18000000-18USD$falsetruefalse4truefalsefalse-461000000-461USD$falsetruefalsexbrli:monetaryItemTypemonetaryMark to market on debt designated at fair value.No definition available.false2Total mark-to-market on debt designated at fair value1Mark-to-market on debt designated at fair value and related derivatives excludes market value changes due to fluctuations in foreign currency exchange rates. Foreign currency translation gains (losses) recorded in derivative related income (expense) associated with debt designated at fair value was a loss of $29 million and a gain of $144 million during the three months ended June 30, 2013 and 2012, respectively, and a gain of $81 million and a gain of $84 million during the six months ended June 30, 2013 and 2012, respectively. Offsetting gains (losses) recorded in derivative related income (expense) associated with the related derivatives was a gain of $29 million and a loss of $144 million during the three months ended June 30, 2013 and 2012, respectively, and a loss of $81 million and a loss of $84 million during the six months ended June 30, 2013 and 2012, respectively.falseFair Value Option - Components of Gain (Loss) on Debt Designated at Fair Value and Related Derivatives (Detail) (USD $)MillionsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.us.hsbc.com/role/FairValueOptionComponentsOfGainLossOnDebtDesignatedAtFairValueAndRelatedDerivativesDetail411