Receivables [Abstract] Loans Loans Receivable Disclosure [Text Block] Loans receivable disclosure. Commitments and Contingencies Disclosure [Abstract] Schedule of Credit Derivatives [Table] Schedule of Credit Derivatives [Table] External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Axis] External Credit Rating By Grouping [Domain] External Credit Rating by Grouping [Domain] External Credit Rating, Investment Grade [Member] External Credit Rating, Investment Grade [Member] External Credit Rating, Non Investment Grade [Member] External Credit Rating, Non Investment Grade [Member] Financial Instrument [Axis] Financial Instrument [Axis] Types of Financial Instruments [Domain] Financial Instruments [Domain] Single name credit default swap [Member] Credit Default Swap [Member] Structured CDS [Member] Other Credit Derivatives [Member] Index credit derivatives [Member] Credit Index Product [Member] Total return swaps [Member] Total Return Swap [Member] Standby Letters of Credit [Member] Standby Letters of Credit [Member] Credit Derivatives Contract Type [Axis] Credit Derivatives Contract Type [Axis] Credit Derivatives Contract Type [Domain] Credit Derivatives Contract Type [Domain] Sell Protection Credit Derivatives [Member] Sell Protection Credit Derivatives [Member] Sell-protection credit derivatives. Credit Derivatives [Line Items] Credit Derivatives [Line Items] Average Life in years Average Term of Credit Risk Derivatives Credit Ratings of the Obligors or the Transactions Guarantor Obligations, Maximum Exposure, Undiscounted Credit Ratings of the Obligors or the Transactions, Total Guarantor Obligations, Maximum Exposure, Undiscounted Amount Guarantor Obligations, Maximum Exposure, Undiscounted Amount Schedule of Financing Receivable, Recorded Investment, Credit Quality Indicator [Table] Schedule of Financing Receivable, Recorded Investment, Credit Quality Indicator [Table] Consumer Loans [Member] Consumer Loan [Member] Financing Receivable, Recorded Investment [Line Items] Financing Receivable, Recorded Investment [Line Items] Residential Mortgage Loan Delinquency Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell Residential Mortgage Loan Delinquency Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell Residential mortgage loan delinquency carried at lower of amortized cost or fair value less cost to sell. Mortgage Loans in Process of Foreclosure, Amount Mortgage Loans in Process of Foreclosure, Amount Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Affiliated Entity [Member] Affiliated Entity [Member] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Credit derivatives [Member] Credit Risk Contract [Member] Financial standby letters of credit, net of participations [Member] Financial Standby Letter of Credit [Member] Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] Notional/Maximum Exposure to Loss Investments, Debt and Equity Securities [Abstract] Gross realized gains Available-for-sale Securities, Gross Realized Gains Gross realized losses Available-for-sale Securities, Gross Realized Losses Net realized gains Available-for-sale Securities, Gross Realized Gain (Loss) Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Fees and Commissions [Member] Fees and Commissions [Member] Fees and Commissions [Member] Other Fees [Member] Other Fees [Member] Other Fees [Member] HSBC Bank Plc [Member] HSBC Bank Plc [Member] HSBC Bank Plc [Member] HSBC Finance Corporation [Member] Hsbc Finance [Member] HSBC finance. HSBC Markets (USA) Inc. (HMUS) and subsidiaries [Member] Hsbc Markets [Member] HSBC Markets. Other Affiliates [Member] Other Affiliates [Member] HSBC Technology and Services (USA) (HTSU) [Member] Hsbc Technology And Services [Member] HSBC technology and services. Related Party Transaction [Line Items] Related Party Transaction [Line Items] Interest income Interest and Dividend Income, Operating Interest expense Interest Expense Net interest income Interest Income (Expense), Net Trading revenue (expense) Trading Gain (Loss) Servicing and other fees with HSBC affiliates: Servicing And Other Fees [Abstract] Servicing and other fees. Total affiliate income Revenue Other Financial Services With Affiliates Revenue Other Financial Services With Affiliates Gain on instruments designated at fair value and related derivatives Gain Loss On Instruments Designated At Fair Value And Related Derivative Fair value changes on fixed rate debt, loans and certain other financial instruments accounted for under fair value option as well as the fair value changes on the related derivatives and realized gains (losses) on the debt related derivatives. Support services from HSBC affiliates: Support Services [Abstract] Support services. Total support services from HSBC affiliates Support Services From Affiliates Servicing and administrative expenses provided by affiliates. Stock based compensation expense with HSBC Allocated Share-based Compensation Expense Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization and Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Intangible Assets Intangible Assets Disclosure [Text Block] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Commercial Loans [Member] Commercial Loan [Member] Class of Financing Receivable [Axis] Class of Financing Receivable, Type [Axis] Class of Financing Receivable [Domain] Class of Financing Receivable, Type [Domain] Construction and Other Real Estate [Member] Commercial Real Estate Portfolio Segment [Member] Business and Corporate Banking [Member] Business and Corporate Banking [Member] Business and Corporate Banking [Member] Global Banking [Member] Global Banking [Member] Global banking. Other Commercial [Member] Other Commercial [Member] Other commercial. Residential Mortgage [Member] Residential Mortgage [Member] Home Equity Mortgages [Member] Home Equity Line of Credit [Member] Credit Cards [Member] Credit Card Receivable [Member] Financing Receivable, Modifications [Line Items] Financing Receivable, Modifications [Line Items] Average balance of TDR loans Trouble Debt Restructuring Average Recorded Investment Trouble debt restructuring average recorded investment. Interest income recognized on TDR loans Trouble Debt Restructuring Interest Income Recognized Trouble debt restructuring interest income recognized. Allowance for Credit Losses Allowance for Credit Losses [Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Loans Loans and Leases Receivable, Net of Deferred Income Net deferred origination fees Net Deferred Origination Costs (Fees) Net Deferred Origination Costs (Fees) Net unamortized premium on loans Net Unamortized Premium On Loans Net unamortized premium on loans. Commercial loans removed from TDR classification Loans Receivable, Commercial Loans Removed from TDR Classification Loans Receivable, Commercial Loans Removed from TDR Classification Weighted average rate of reduction Weighted Average Rate Reduction on TDR Loans Weighted Average Rate Reduction on TDR Loans Variable Interest Entities [Abstract] Variable Interest Entities [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other assets [Member] Other Assets [Member] Long-term debt [Member] Long-term Debt [Member] Interest, taxes and other liabilities [Member] Other Liabilities [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable interest entities [Member] Variable Interest Entity, Primary Beneficiary [Member] Low income housing limited liability partnership [Member] Low Income Housing Limited Liability Partnership [Member] Low Income Housing Limited Liability Partnership [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Consolidated Assets Variable Interest Entity, Consolidated, Carrying Amount, Assets Consolidated Liabilities Variable Interest Entity, Consolidated, Carrying Amount, Liabilities Carrying Value and Contractual Amounts of our Sell Protection Credit Derivatives and Major Off-Balance Sheet Guarantee Arrangements Schedule of Guarantor Obligations [Table Text Block] Net Credit Derivative Positions Schedule Of Net Credit Derivative Positions Table [Table Text Block] Schedule Of Net Credit Derivative Positions Table [Table Text Block] Summary of Credit Ratings of Credit Risk Related Guarantees Summary Of Credit Ratings Of Credit Risk Related Guarantees Table [Table Text Block] Summary Of Credit Ratings Of Credit Risk Related Guarantees Table [Table Text Block] Summary of Change in Estimated Repurchase Liability for Loans Sold to GSEs and Other Third Parties Summary Of Change In Estimated Repurchase Liability For Loans Sold To Government Sponsored Entities And Other Third Parties Table [Table Text Block] Summary Of Change In Estimated Repurchase Liability For Loans Sold To Government Sponsored Entities And Other Third Parties Table [Table Text Block] Summary of Pledged Assets Included in Consolidated Balance Sheet Summary Of Pledged Assets Included In Consolidated Balance Sheet Table [Table Text Block] Summary Of Pledged Assets Included In Consolidated Balance Sheet Table [Table Text Block] Offsetting Assets and Liabilities Offsetting Assets and Liabilities [Table Text Block] Offsetting Assets and Liabilities [Table Text Block] Class of Collateral Pledged and Remaining Contractual Maturity of Repurchase Agreements Accounted for as Secured Borrowings Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table Text Block] Schedule of Other than Temporary Impairment, Credit Losses Recognized in Earnings [Table] Schedule of Other than Temporary Impairment, Credit Losses Recognized in Earnings [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Other Revenues [Member] Other Revenues [Member] Other Revenues [Member] Debt Security [Axis] Debt Security [Axis] Major Types of Debt Securities [Domain] Major Types of Debt Securities [Domain] Held-to-maturity Securities [Member] Held-to-maturity Securities [Member] Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items] Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items] Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward] Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward] Beginning balance of credit losses on held-to-maturity debt securities for which a portion of an other-than-temporary impairment was recognized in other comprehensive income (loss) Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held Increase in credit losses for which an other-than-temporary impairment was previously recognized Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses Ending balance of credit losses on held-to-maturity debt securities for which a portion of an other-than-temporary impairment was recognized in other comprehensive income (loss) Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] U.S. Treasury [Member] US Treasury Securities [Member] US Government sponsored enterprises [Member] US Government-sponsored Enterprises Debt Securities [Member] US Government agency issued or guaranteed [Member] US Government Agencies Debt Securities [Member] Obligations of U.S. states and political subdivision [Member] US States and Political Subdivisions Debt Securities [Member] Asset backed securities [Member] Asset-backed Securities [Member] Foreign debt securities [Member] Foreign Debt Securities [Member] Foreign Debt Securities [Member] Equity securities [Member] Equity Securities [Member] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Number of securities available for sale in one year or less Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Number Of Securities Available for sale securities continuous unrealized loss position less than twelve months number of securities. Securities available-for-sale gross unrealized losses one year or less Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Securities available-for-sale aggregate fair value of investment one year or less Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Number of Securities available for sale greater than one year Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Number Of Securities Available for sale securities continuous unrealized loss position twelve months or longer number of securities. Securities available-for-sale gross unrealized losses greater than one year Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Securities available-for-sale aggregate fair value of investment greater than one year Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Number of securities held-to-maturity in one year or less Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Number Of Securities Held to maturity securities continuous unrealized loss position less than twelve months number of securities. Securities held-to-maturity gross unrealized losses one year or less Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Securities held-to-maturity aggregate fair value of investment one year or less Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Securities held-to-maturity greater than one year Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Number Of Securities Held to maturity securities continuous unrealized loss position twelve months or longer number of securities. Securities held-to-maturity gross unrealized losses greater than one year Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Securities held-to-maturity aggregate fair value of investment greater than one year Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Litigation and Regulatory Matters Legal Matters and Contingencies [Text Block] Schedule of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] TDR Loans Financing Receivable, Modifications, Recorded Investment Schedule of Financing Receivable, Allowance for Credit Losses [Table] Schedule of Financing Receivable, Allowance for Credit Losses [Table] Residential Mortgages [Member] Other consumer [Member] Consumer Portfolio Segment [Member] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Line Items] Allowance for Loan and Lease Losses [Roll Forward] Allowance for Loan and Lease Losses [Roll Forward] Balance at beginning of period Loans and Leases Receivable, Allowance Provision for credit losses Provision for Loan and Lease Losses Charge offs Allowance for Loan and Lease Losses, Write-offs Recoveries Allowance for Loan and Lease Loss, Recovery of Bad Debts Net (charge offs) recoveries Allowance for Loan and Lease Losses Write-offs, Net Balance at end of period Ending balance: collectively evaluated for impairment Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment Ending balance: individually evaluated for impairment Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment Total allowances for credit losses Collectively evaluated for impairment Financing Receivable, Collectively Evaluated for Impairment Individually evaluated for impairment Financing Receivable, Individually Evaluated for Impairment Loans carried at the lower of amortized cost or fair value less cost to sell Loans Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell Loans carried at the lower of amortized cost or fair value less cost to sell. Total loans Fair Value Disclosures [Abstract] Fair Value Measurements, Recurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Other liabilities [Member] Eligible Item or Group for Fair Value Option [Axis] Eligible Item or Group for Fair Value Option [Axis] Fair Value, Option, Eligible Item or Group [Domain] Fair Value, Option, Eligible Item or Group [Domain] Domestic Deposits [Member] Deposits [Member] Borrowings [Member] Borrowings [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Foreign exchange contracts [Member] Foreign Exchange Contract [Member] Equity contracts [Member] Equity Contract [Member] Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Option pricing model [Member] Option Pricing Model [Member] Option pricing model. Option adjusted discounted cash flows [Member] Option Adjusted Discounted Cash Flows [Member] Option adjusted discounted cash flows. Government debt securities issued by foreign entities [Member] Foreign Government Debt Securities [Member] Derivative Instrument Risk [Axis] Derivative Instrument [Axis] Derivative Contract Type [Domain] Derivative Contract [Domain] Derivatives [Member] Derivative Assets [Member] Derivative assets. Derivative Liabilities [Member] Derivative Liabilities [Member] Derivative liabilities. Credit contracts [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Weighted Average [Member] Weighted Average [Member] Impaired Loans [Member] Impaired Loans [Member] Impaired Loans. Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair value of assets Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Loss severity, trust preferred securities Debt Obligation, Collateralized, Loss Severity Rate Debt Obligation, Collateralized, Loss Severity Rate Fair Value Assets, Transfers Out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Fair Value Liability, Transfers Out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3 Fair Value Liability, Transfers Into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3 Fair Value Inputs, Implied Volatility Currency Pairs Fair Value Assumptions, Expected Volatility Rate Fair Value Inputs, Equity/Equity Index Volatility Fair Value Inputs, Equity to Equity Index Volatility Fair Value Inputs, Equity to Equity Index Volatility Average deviation of implied volatility, foreign currency pair Derivative Instrument, Foreign Currency, Trade Market , Implied Volatility Deviation Derivative Instrument, Foreign Currency, Trade Market , Implied Volatility Deviation Average deviation of implied volatility, at-the-money equity option Derivative Instrument, Equity, Trade Market, Implied Volatility Derivative Instrument, Equity, Trade Market, Implied Volatility Fair Value Inputs, Equity/Equity and Equity/Index Correlation Fair Value Inputs, Equity to Equity and Equity to Index Correlation Fair Value Inputs, Equity to Equity and Equity to Index Correlation Fair Value Inputs, Loss Severity Fair Value Inputs, Loss Severity Deferred fees on standby letters of credit Deferred Revenue and Credits Revaluation period Fair Value Measurements, Minimum Period of Evaluation for Reduction in Fair Value Fair Value Measurements, Minimum Period of Evaluation for Reduction in Fair Value Threshold period for troubled debt restructuring status Threshold Period for Troubled Debt Restructuring Status Threshold Period for Troubled Debt Restructuring Status Loans which were classified as TDR loans during the previous 12 months which became contractually delinquent Tdr Loans During Previous Months Which Became Contractually Delinquent TDR loans during previous months which became contractually delinquent. Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Criticized [Member] Criticized [Member] Special Mention [Member] Special Mention [Member] Substandard [Member] Substandard [Member] Doubtful [Member] Doubtful [Member] Total loans Segment Reporting [Abstract] Business Segments Segment Reporting Disclosure [Text Block] Annualized constant prepayment rate (CPR) Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed Constant discount rate Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate Weighted average life Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Weighted Average Life Summary on Reconciliation of Results under Group Reporting Basis to US GAAP Summary on Reconciliation of Results under Group Reporting Basis to US GAAP [Table Text Block] Summary on Reconciliation of Results under Group Reporting Basis to US GAAP [Table Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Credit Rating, Moody's [Axis] Credit Rating, Moody's [Axis] External Credit Rating, Moody's [Domain] External Credit Rating, Moody's [Domain] Moody's Long Term Rating Aa3 [Member] Moody's, Aa3 Rating [Member] Moody's Long Term Rating A1 [Member] Moody's, A1 Rating [Member] Credit Rating, Standard & Poor's [Axis] Credit Rating, Standard & Poor's [Axis] External Credit Rating, Standard & Poor's [Domain] External Credit Rating, Standard & Poor's [Domain] S&P Long Term Rating A plus [Member] Standard & Poor's, A+ Rating [Member] S&P Long Term Rating A [Member] Standard & Poor's, A Rating [Member] Total Credit Rating Scenario of Derivatives Additional Collateral, Aggregate Fair Value Fair Value Option [Abstract] Fair Value Option [Abstract] Fair Value, Option, Quantitative Disclosures [Table] Fair Value, Option, Quantitative Disclosures [Table] Loans Receivable [Member] Loans Receivable [Member] Short-term Borrowings [Member] Securities Loaned or Sold under Agreements to Repurchase [Member] Long-term debt [Member] Deposits [Member] Fair Value, Option, Quantitative Disclosures [Line Items] Fair Value, Option, Quantitative Disclosures [Line Items] Commercial loans held for sale, Fair Value Loans Held-for-sale, Fair Value Disclosure Commercial loans held for sale, Unpaid Principal Balance Unpaid Principal Balance Commercial Syndicated Loans Held For Sale Carried at Fair Value Unpaid Principal Balance Commercial Syndicated Loans Held For Sale Carried at Fair Value Repurchase agreements, Fair Value Short-term Debt, Fair Value Repurchase agreements, Unpaid Principal Balance Unpaid Principle Balance, Repurchase Agreements Unpaid Principle Balance, Repurchase Agreements Fixed rate long-term debt, Fair Value Fixed Rate Debt Accounted For Under Fair Value Option Fixed-rate debt accounted for under fair value option. Fixed rate long-term debt, Unpaid Principal Balance Unpaid Principal Balance On Fixed Rate Debt Accounted For Under Fvo Fair Value Option Unpaid principal balance on fixed-rate debt accounted for under FVO. Hybrid Instruments, Fair Value Fair Value Option, Fair Value Carrying Amount, Liabilities, Hybrid Instruments Fair Value Option, Fair Value Carrying Amount, Liabilities, Hybrid Instruments Hybrid Instruments, Unpaid Principal Balance Unpaid Principal Balance On Hybrid Instruments at Fair Value Option Unpaid Principal Balance On Hybrid Instruments at Fair Value Option Accounting Changes and Error Corrections [Abstract] New Accounting Pronouncements New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Schedule of Financing Receivables Past Due [Table] Schedule of Financing Receivables Past Due [Table] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Domain] Financing Receivables, Period Past Due [Domain] Financing Receivables, 30 to 89 Days Past Due [Member] Financing Receivables, 30 to 89 Days Past Due [Member] Financing Receivables, 30 to 89 Days Past Due [Member] Financing Receivables, Equal to Greater than 90 Days Past Due [Member] Financing Receivables, Equal to Greater than 90 Days Past Due [Member] Financing Receivable, Recorded Investment, Past Due [Line Items] Financing Receivable, Recorded Investment, Past Due [Line Items] Total Days Past Due, 30 Days or More Financing Receivable, Recorded Investment, Past Due Current Financing Receivable, Recorded Investment, Current Equity [Abstract] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Trading Assets And Liabilities [Abstract] Trading Assets And Liabilities [Abstract] Trading Assets [Member] Trading Assets [Member] Trading assets. Trading Liabilities [Member] Trading Liabilities [Member] Derivatives included in trading assets, amount offset Derivative Asset, Collateral, Obligation to Return Cash, Offset Derivatives included in trading liabilities, amount offset Derivative Liability, Collateral, Right to Reclaim Cash, Offset Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Value [Member] Reported Value Measurement [Member] Estimate of fair value [Member] Estimate of Fair Value Measurement [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Deposits Without Fixed Maturities [Member] Deposits Without Fixed Maturities [Member] Deposits Without Fixed Maturities [Member] Deposits With Fixed Maturities [Member] Deposits With Fixed Maturities [Member] Deposits With Fixed Maturities [Member] Fair Value Of Other Financial Instrument [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Short-term financial assets Short Term Financial Assets Fair Value Short-term financial assets fair value disclosure. Federal funds sold and securities purchased under resale agreements Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure Non-derivative trading assets Non Derivative Trading Assets Fair Value Non-derivative trading assets fair value disclosure. Derivatives Derivative Asset Securities Securities, Fair Value Disclosure Securities, Fair Value Disclosure Commercial loans, net of allowance for credit losses Loans and Leases Receivable, Net Amount, Commercial Commercial loans designated under fair value option and held for sale Fair Value of Commercial Syndicated Loans Held For Sale Fair Value of Commercial Syndicated Loans Held For Sale Loans held for sale Consumer loans, net of allowance for credit losses Loans and Leases Receivable, Net Amount, Consumer Short-term financial liabilities Short-term Financial Liabilities, Fair Value Short-term Financial Liabilities, Fair Value Deposits Deposits, Fair Value Disclosure Deposits designated under fair value option Interest Bearing Deposits Domestic Fair Value Option Disclosure Interest bearing deposits domestic fair value option disclosure. Non-derivative trading liabilities Non Derivative Trading Liability Non derivative trading liability. Derivatives Derivative Liability Short-term borrowings designated under fair value option Long-term debt Long-term Debt, Fair Value Long-term debt designated under fair value option Long Term Debt Fair Value Option Disclosure This element represents the portion of long term debt that the entity has elected to value at fair value under the fair value option. Fair value of MSRs: Servicing Asset at Fair Value, Amount [Roll Forward] Beginning balance Servicing Asset at Fair Value, Amount Changes in fair value due to changes in valuation model inputs or assumptions Servicing Asset at Fair Value, Changes in Fair Value Resulting from Changes in Valuation Inputs Reductions related to customer payments Servicing Asset at Fair Value, Other Changes in Fair Value Ending balance Statement of Comprehensive Income [Abstract] Net income Net Income (Loss) Attributable to Parent Net change in unrealized gains (losses), net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Investment securities Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Other-than-temporarily impaired debt securities held-to-maturity Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, Net of Tax, Portion Attributable to Parent, Held-to-maturity Securities Derivatives designated as cash flow hedges Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent Pension and post-retirement benefit plans Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Total other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Trading Assets and Liabilities Trading Assets And Liabilities [Table Text Block] Trading Assets And Liabilities [Table Text Block] Derivative [Table] Derivative [Table] Interest rate contracts [Member] Interest Rate Contract [Member] Commodities, equities and precious metals contracts [Member] Commodity and Equity Contract [Member] Commodity and Equity Contract [Member] Derivative, by Nature [Axis] Derivative, by Nature [Axis] Derivative, Name [Domain] Derivative, Name [Domain] Futures and forwards [Member] Futures And Forwards [Member] Futures and forwards. Swaps [Member] Swap [Member] Options written [Member] Options Written [Member] Options written. Options purchased [Member] Options Purchased [Member] Options purchased. Swaps, futures and forwards [Member] Swaps Futures And Forwards [Member] Swaps, futures and forwards. Spot [Member] Spot [Member] Spot. Derivative [Line Items] Derivative [Line Items] Total Derivative, Notional Amount Support Services From Affiliates [Member] Support Services From Affiliates [Member] Support Services From Affiliates [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Floating Rate Notes [Member] Floating Rate Note [Member] Floating Rate Note [Member] Hnah [Member] Hnah [Member] HNAH. HSBC North America Inc. HNAI [Member] HNAI [Member] HNAI [Member] HMUS [Member] Hmus [Member] HMUS. HSBC Bank Brasil [Member] HSBC Bank Brasil [Member] HSBC Bank Brasil [Member] HSBC Mexico [Member] HSBC Mexico [Member] HSBC Mexico [Member] Regency [Member] Regency [Member] Regency [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Senior debt [Member] Senior Notes [Member] Subordinated Debt [Member] Subordinated Debt [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Extended Uncommitted Revolving Credit Facility [Member] Extended Uncommitted Revolving Credit Facility [Member] Extended uncommitted revolving credit facility. Extended committed revolving credit facility [Member] Extended Committed Revolving Credit Facility [Member] Extended committed revolving credit facility. Debt issued Debt Instrument, Face Amount Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Amount outstanding under the loan agreement Long-term Line of Credit Extended loans and lines of credit Loan And Lease Receivable Extended Loan And Line Of Credit Facility Loan and lease receivable extended loan and line of credit facility. Debt term Debt Instrument, Term Loans and Leases Receivable, Related Parties Loans and Leases Receivable, Related Parties Maximum maturity for borrowings under uncommitted revolving credit agreement Period Of Maturity Of Line Of Credit Period of maturity of line of credit. Loan And Lease Receivable Revolving Line Of Credit Outstanding Loan And Lease Receivable Revolving Line Of Credit Outstanding Loan and lease receivable revolving line of credit outstanding. Credit agreement, amount maturing September 2017 Related Party Transaction, Lending Arrangement, Line of Credit Facility, Amount Maturing Period One Related Party Transaction, Lending Arrangement, Line of Credit Facility, Amount Maturing Period One Credit agreement amount maturing January 2018 Related Party Transaction, Lending Arrangement, Line of Credit Facility, Amount Maturing Period Two Related Party Transaction, Lending Arrangement, Line of Credit Facility, Amount Maturing Period Two Credit agreement amount maturing September 2018 Related Party Transaction, Lending Arrangement, Line of Credit Facility, Amount Maturing Period Three Related Party Transaction, Lending Arrangement, Line of Credit Facility, Amount Maturing Period Three Related Party Transaction, Liquidity Facility, Notional Amount Related Party Transaction, Liquidity Facility, Notional Amount Related Party Transaction, Liquidity Facility, Notional Amount Derivative, notional amount Fair value of derivative assets and liabilities Derivative, Fair Value, Net Carrying Amount At Period End of Residential Mortgage Loans Serviced By HSBC Finance Carrying Amount At Period End of Residential Mortgage Loans Serviced By Affiliates Carrying Amount At Period End of Residential Mortgage Loans Serviced By Affiliates Rent from related party Rental Income, Nonoperating Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Gain (Loss) on Instruments Designated at Fair Value and Related Derivatives [Member] Gain (loss) on Instruments Designated at Fair Value and Related Derivatives [Member] Gain (loss) on Instruments Designated at Fair Value and Related Derivatives [Member] Residential mortgage banking revenue [Member] Residential Mortgage Banking Revenue [Member] Residential mortgage banking revenue. Other Income [Member] Other Income [Member] Precious metals contracts [Member] Commodity Contract [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Mark-to-market on the related derivatives Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Goodwill Goodwill Accumulated impairment loss Goodwill, Impaired, Accumulated Impairment Loss Book value as percentage of fair value (percent) Reporting Unit, Carrying Value as Percentage of Fair Value Reporting Unit, Carrying Value as Percentage of Fair Value Banking and Thrift [Abstract] Capital Amounts and Ratios in Accordance With Current Banking Regulations Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Income Statement [Abstract] Statement [Table] Statement [Table] Statement [Line Items] Statement [Line Items] OTTI losses in the non-credit component of such impaired securities recognized in AOCI, net of tax Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income Loss, Before Reclassification Adjustments, Net of Tax Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income Loss, Before Reclassification Adjustments, Net of Tax Total commercial Loans and Leases Receivable, Commercial, Net of Deferred Income Total consumer Loans and Leases Receivable, Consumer, Net of Deferred Income Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] U.S. Treasury, U.S. Government agencies and sponsored entities [Member] US Treasury and Government [Member] Foreign Debt Securities [Member] Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Maturity Overnight and Continuous [Member] Maturity Overnight and Continuous [Member] Maturity Overnight and Continuous [Member] Maturity up to 30 Days [Member] Maturity Less than 30 Days [Member] Maturity 30 to 90 Days [Member] Maturity 30 to 90 Days [Member] Maturity Greater than 90 Days [Member] Maturity Greater than 90 Days [Member] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Collateral pledged and remaining contractual maturity of repurchase agreements accounted for as secured borrowings Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement Fair Value Measurements Fair Value Disclosures [Text Block] Summary of Assets and Liabilities Related to Consolidated Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Variable Interests Held by Us and Our Maximum Exposure to Loss Rising From Our Involvements in Those VIEs Schedule Of Additional Information On Unconsolidated Vies [Table Text Block] Schedule Of Additional Information On Unconsolidated Vies [Table Text Block] Document and Entity Information [Abstract] Document and Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Mortgage servicing rights [Member] Servicing Contracts [Member] Fair Value by Asset Class [Domain] Trading Securities, excluding derivatives [Member] Trading Securities [Member] Derivative financial assets [Member] Derivative Financial Instruments, Assets [Member] Securities available-for-sale [Member] Available-for-sale Securities [Member] Loans [Member] Loans [Member] Mortgage servicing rights [Member] Finite-Lived Intangible Assets [Member] Derivatives [Member] Derivative [Member] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Domestic Deposits [Member] Deposits In Domestic Offices [Member] Deposits in domestic offices. Trading liabilities excluding derivatives [Member] Trading Liabilities Excluding Derivatives [Member] Trading Liabilities Excluding Derivatives [Member] Derivative Financial Instruments, Liabilities [Member] Derivative Financial Instruments, Liabilities [Member] Short-term borrowings [Member] Short-term Debt [Member] Long-term Debt [Member] Derivatives netting [Member] Derivatives, Fair Value, Netting [Member] Derivatives, Fair Value, Netting [Member] Collateralized debt obligations [Member] Collateralized Debt Obligations [Member] Residential Mortgage Backed Securities [Member] Residential Mortgage Backed Securities [Member] Student Loan Backed Securities [Member] Student Loan Backed Securities [Member] Student Loan Backed Securities [Member] Corporate and other domestic debt securities [Member] Domestic Corporate Debt Securities [Member] Corporate debt securities issued by foreign entities [Member] Foreign Corporate Debt Securities [Member] Precious metals [Member] Commodities Investment [Member] Commercial Mortgage Backed Securities [Member] Commercial Mortgage Backed Securities [Member] Home Equity Backed Securities [Member] Home Equity Backed Securities [Member] Home equity backed securities. Other securities [Member] Other Debt Obligations [Member] Gross Balance, Assets Assets, Fair Value Disclosure, Recurring Netting, Assets Derivative Asset, Fair Value, Gross Liability Net Balance, Assets Assets, Fair Value Disclosure, Recurring, Net Assets, Fair Value Disclosure, Recurring, Net Gross Balance, Liabilities Liabilities, Fair Value Disclosure, Recurring Netting Liabilities Derivative Liability, Fair Value, Gross Asset Net Balance, Liabilities Liabilities, Fair Value Disclosure, Recurring, Net Liabilities, Fair Value Disclosure, Recurring, Net Trading assets Trading Assets The carrying amount of assets as of the balance sheet date that pertain to principal and customer trading transactions, or which may be incurred with the objective of generating a profit from short-term fluctuations in price as part of an entity's market-making, hedging and proprietary trading. Examples include trading securities, trading derivatives and commodities. Trading liabilities Trading Liabilities TDR Loans Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell Residential Mortgage Loan TDR Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell Residential Mortgage Loan TDR Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell Basis adjustments for active fair value hedges which increased (decreased) the carrying amount of our debt (less than $1 million for the 3 and 6 months ended June 30, 2015) Fair Value Hedge Basis Adjustment, Increase (Decreases) in Carrying Amount Of Debt Fair value hedge basis adjustment, increase (decrease) in the carrying amount of debt. Amortization of basis adjustments related to terminated and/or re-designated fair value hedge relationships of our debt Amortization of Basis Adjustments Related To Terminated and or Redesignated Fair Value Hedge Relationships of Company Debt Amortization of basis adjustments related to terminated and/or redesignated fair value hedge relationships of Company debt. Accumulated unamortized basis adjustment for terminated and/or re-designated fair value hedges of our debt Deferred (Gain) Loss on Discontinuation of Fair Value Hedge Basis adjustments for active fair value hedges which increased (decreased) the carrying amount of available for sale securities Increase (Decrease) in Basis Adjustment for Active Fair Value Hedges of Available for Sale Securities Increase (Decrease) in Basis Adjustment for Active Fair Value Hedges of Available for Sale Securities Accumulated unamortized basis adjustment for active fair value hedges which increased (decreased) the carrying amount of our available for sale securities Increase (Decrease) In Accumulated Unamortized Adjustments For Fair Value Hedges As Available For Sale Securities Increase (Decrease) In Accumulated Unamortized Adjustments For Fair Value Hedges As Available For Sale Securities Amortization of basis adjustments related to terminated and/or re-designated cash flow hedge relationships Amortization of Basis Adjustments Related To Terminated And Or Redesignated Cash Flow Relationships Amortization of Basis Adjustments Related To Terminated and or Redesignated Cash Flow Hedge Relationships Next twelve months, reclassification of remaining losses to earnings resulting from cash flow hedges Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Aggregate fair value of all derivative instruments with credit-risk-related contingent Credit Risk Derivative Liabilities, at Fair Value Collateral already posted aggregate fair value Collateral Already Posted, Aggregate Fair Value Summary of Related Party Transactions Summary Of Related Party Financial Information Table [Table Text Block] Summary Of Related Party Financial Information Table [Table Text Block] Schedule of Assets by Related Party Schedule of Assets by Related Party [Table Text Block] Schedule of Assets by Related Party [Table Text Block] Asset-backed commercial paper conduits [Member] Asset Backed Commercial Paper Conduits [Member] Asset-backed commercial paper conduits. Structured note vehicles [Member] Structured Note Vehicles [Member] Structured note vehicles. Low income housing partnerships [Member] Variable Interest Held Classified as Assets Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets Variable Interests Held Classified as Liabilities Variable Interest Entity, Nonconsolidated, Carrying Amount, Liabilities Total Assets in Unconsolidated VIEs Variable Interest Entity, Nonconsolidated, Total Assets Variable Interest Entity, Nonconsolidated, Total Assets Maximum Exposure to Loss Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Schedule of Trading Securities and Other Trading Assets [Table] Trading Securities [Table] Federal National Mortgage Association Certificates and Obligations (FNMA) [Member] Federal National Mortgage Association Certificates and Obligations (FNMA) [Member] Corporate and foreign bonds [Member] Corporate And Foreign Bonds [Member] Corporate And Foreign Bonds [Member] Securities sold, not yet purchased [Member] Securities Sold, Not yet Purchased [Member] Schedule of Trading Securities and Other Trading Assets [Line Items] Schedule of Trading Securities and Other Trading Assets [Line Items] Securities purchased under agreements to resell, Gross Amounts Recognized Securities Purchased under Agreements to Resell, Gross Securities purchased under agreements to resell, Gross Amounts Offset in the Balance Sheet Securities Purchased under Agreements to Resell, Liability Securities Purchased under Agreements to Resell Securities Purchased under Agreements to Resell Securities purchased under agreements to resell, Gross Amounts Not Offset in the Balance Sheet, Financial Instruments Securities Purchased under Agreements to Resell, Collateral, Obligation to Return Securities Securities purchased under agreements to resell, Gross Amounts Not Offset in the Balance Sheet, Cash Collateral Receive / Pledged Securities Purchased under Agreements to Resell, Collateral, Obligation to Return Cash Securities purchased under agreements to resell, Net amount Securities Purchased under Agreements to Resell, Amount Offset Against Collateral Securities sold under repurchase agreements, Gross Amounts Recognized Securities Sold under Agreements to Repurchase, Gross Securities sold under repurchase agreements, Gross Amounts Offset in the Balance Sheet Securities Sold under Agreements to Repurchase, Asset Securities sold under repurchase agreements, Net Amounts Presented in the Balance Sheet Securities Sold under Agreements to Repurchase Securities sold under repurchase agreements, Gross Amounts Not Offset in the Balance sheet, Financial Instruments Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities Securities sold under repurchase agreements, Gross Amounts Not Offset in the Balance Sheet, Cash Collateral Received / Pledged Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash Securities sold under repurchase agreements, Net amount Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral Performing Loans Performing Loans Performing loans. Nonaccrual Loans Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest Accruing Loans Contractually Past Due 90 days or More Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing Summary of Changes in the Allowance for Credit Losses and the Related Loan Balance by Product Summary Of Changes In Allowance For Credit Losses And Related Loan Balance By Product [Table Text Block] Summary Of Changes In Allowance For Credit Losses And Related Loan Balance By Product [Table Text Block] Trading Gain (Loss) [Member] Trading Gain (Loss) [Member] Trading Gain (Loss) [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value Assets, Beginning Balance Fair Value Assets, Gains (Losses) Included In Revenue Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Fair Value Assets, Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Fair Value Assets, Issuances Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances Fair Value Assets, Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Fair Value Assets, Transfers Into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Fair Value Assets, Transfers Out of Level 3 Fair Value Assets, Ending Balance Fair Value Assets, Current Period Unrealized Gains (Losses) Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value Liability, Beginning Balance Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value Fair Value Liability, Gains (Losses) Included In Revenue Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Fair Value Liability, Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Fair Value Liability, Issuances Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances Fair Value Liability, Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Fair Value Liability, Transfers Into Level 3 Fair Value Liability, Ending Balance Fair Value Liability, Current Period Unrealized Gains (Losses) Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss) Subprime [Member] Subprime [Member] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Residential Portfolio Segment [Member] Residential Portfolio Segment [Member] Commercial Loans - Fair Value Option [Member] Commercial Loans - Syndicated Fair Value Option [Member] Commercial Loans - Syndicated Fair Value Option [Member] Commercial Real Estate [Member] Total loans held for sale Loans Receivable Held-for-sale, Amount Valuation allowance Valuation Allowances and Reserves, Balance Components Of Gain On Instruments At Fair Value And Related Derivatives [Table] Components Of Gain On Instruments At Fair Value And Related Derivatives [Table] Components Of Gain On Instruments At Fair Value And Related Derivatives [Table] Loans [Member] Hybrid Instrument [Member] Hybrid Instrument [Member] Components Of Gain On Instruments At Fair Value And Related Derivatives [Line Items] Components Of Gain On Instruments At Fair Value And Related Derivatives [Line Items] Components Of Gain On Instruments At Fair Value And Related Derivatives [Line Items] Interest rate and other components Fair Value, Option, Interest Rate and Other Components, Gains (Losses) Fair Value, Option, Interest Rate and Other Components, Gains (Losses) Credit risk component, assets Fair Value, Option, Credit Risk, Gains (Losses) on Assets Credit risk component, liabilities Fair Value, Option, Credit Risk, Gains (Losses) on Liabilities Credit risk component, total Fair Value, Option, Credit Risk, Gains (Losses), Net Fair Value, Option, Credit Risk, Gains (Losses), Net Total mark-to-market on financial instruments designated at fair value Fair Value, Option, Changes in Fair Value, Gain (Loss) Net Realized Gain Losses On Related Long Term Debt Derivatives Net Realized Gain Losses On Related Long Term Debt Derivatives Net realized gain losses on the related long-term debt derivatives. Gain (loss) on instruments designated at fair value and related derivatives Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Purchased credit card relationships [Member] Customer Relationships [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Outstanding principal balances at period end of residential mortgage loans serviced for others Outstanding Principal Balances At Period End Of Residential Mortgage Loans Service For Others Outstanding principal balances at period end. Servicing fees collected Bank Servicing Fees Outstanding principal balances at period end of residential mortgage loans owned and serviced for others Outstanding Principal Balances At Period End Of Residential Mortgage Loans Owned and Serviced For Others Outstanding Principal Balances At Period End Of Residential Mortgage Loans Owned and Serviced For Others Purchased from HSBC Finance account of credit card Credit Card Receivable Balance Associated With Account Relationships Purchased Credit card receivable balance associated with account relationships purchased. Credit card receivables not being sold to Capital One at a fair value Fair Value Of Intangible Related To Asset Account Relationships Purchased Fair value of intangible related to asset account relationships purchased. Fair value of Intangible asset related to account relationships purchased include in branch sale Fair Value Of Intangible Asset Related To Account Relationships Purchased Include In Branch Sale Fair value of Intangible asset related to account relationships purchased include in branch sale. Fair value of Intangible asset related to account relationships purchased retained Fair Value Of Intangible Asset Related To Account Relationships Purchased Retained Fair value of Intangible asset related to account relationships purchased retained. Useful life Finite-Lived Intangible Asset, Useful Life Schedule of Derivative Instruments Schedule of Derivative Instruments [Table Text Block] Schedule of Gains and Losses on Fair Value Hedging Instruments Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block] Schedule of Gains and Losses on Cash Flow Hedging Instruments Schedule Of Cash Flow Hedge Instruments Statement Of Financial Position Location [Table Text Block] Schedule Of Cash Flow Hedge Instruments Statement Of Financial Position Location Table [Text Block] Schedule of Gains and Losses on Derivative Instruments Included in Trading Activities Schedule of Derivative Instruments Included in Trading Activities [Table Text Block] Schedule of Gains and Losses on Derivative Instruments Held for Non-qualifying Hedging Activities Gains And Losses On Derivative Instruments Held For Other Purposes [Table Text Block] Gains And Losses On Derivative Instruments Held For Other Purposes [Table Text Block] Credit-Risk Related Contingent Features Credit Risk Related Contingent Features [Table Text Block] Credit Risk Related Contingent Features [Table Text Block] Notional Value of Derivative Contracts Notional Value Of Derivative Contracts [Table Text Block] Notional Value Of Derivative Contracts [Table Text Block] Performance (non-financial) guarantees, net of participations [Member] Performance Guarantee [Member] Liquidity asset purchase agreements [Member] Liquidity Asset Purchase Agreements [Member] Liquidity asset purchase agreements. Carrying Value Guarantor Obligations, Current Carrying Value Unrealized gains (losses) on investment securities: Unrealized Gains On Securities Available For Sale Not Other Than Temporarily Impaired [Roll Forward] Unrealized Gains On Securities Available For Sale Not Other Than Temporarily Impaired [Roll Forward] Balance at beginning of period Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Other comprehensive income for period: Other Comprehensive Income Available For Sale Securities Not Other Than Temporarily Impaired Net Of Tax [Abstract] Other comprehensive income available for sale securities not other than temporarily impaired net of tax. Net unrealized gains (losses) arising during period, net of tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Reclassification adjustment for gains realized in net income, net of tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Amortization of net unrealized losses on securities transferred from available-for-sale to held-to-maturity realized in net income, net of tax Other Comprehensive Income (Loss), Amortization of Net Unrealized Losses on Transfers from Available-for-Sale to Held-to Maturity Securities, Net of Tax Other Comprehensive Income (Loss), Amortization of Net Unrealized Losses on Transfers from Available-for-Sale to Held-to Maturity Securities, Net of Tax Total other comprehensive income (loss) for period Balance at end of period Unrealized losses on other-than-temporarily impaired debt securities held-to-maturity: Unrealized losses on other-than-temporarily impaired debt securities held-to-maturity [Roll Forward] Unrealized losses on other-than-temporarily impaired debt securities held-to-maturity [Roll Forward] Balance at beginning of period Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Held-to-maturity, Debt Securities Other comprehensive income for period: Other Comprehensive Income (Loss), Other Than Temporary Impairment, Not Credit Loss, Net of Tax, Debt Securities, Held to Maturity [Abstract] Other Comprehensive Income (Loss), Other Than Temporary Impairment, Not Credit Loss, Net of Tax, Debt Securities, Held to Maturity [Abstract] Reclassification adjustment related to the accretion of unrealized other-than-temporary impairment, net of tax Other than Temporary Impairment Losses, Investments, Reclassification Adjustment of Noncredit Portion, Net of Tax, Held-to-maturity Securities Other than Temporary Impairment Losses, Investments, Reclassification Adjustment of Noncredit Portion, Net of Tax, Held-to-maturity Securities Total other comprehensive income for period Balance at end of period Unrealized (losses) gains on derivatives classified as cash flow hedges: Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent [Roll Forward] Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent [Roll Forward] Balance at beginning of period Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Other comprehensive income (loss) for period: Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract] Net unrealized losses arising during period, net of tax Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Reclassification adjustment of losses realized in net income, net of tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Total other comprehensive income (loss) for period Balance at end of period Pension and postretirement benefit liability: Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, Portion Attributable to Parent [Roll Forward] Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, Portion Attributable to Parent [Roll Forward] Balance at beginning of period Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax Other comprehensive income for period: Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax [Abstract] Change in unfunded pension and postretirement liability, net of tax Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax Total other comprehensive income for period Balance at end of period Total accumulated other comprehensive income (loss) at end of period Accumulated Other Comprehensive Income (Loss), Net of Tax AOCI included in pretax unrealized losses Accumulated Other Comprehensive Income (Loss), Net Unrealized Gains (Losses) on Transfers from Available-for-Sale to Held-to Maturity Securities, Before Tax Accumulated Other Comprehensive Income (Loss), Net Unrealized Gains (Losses) on Transfers from Available-for-Sale to Held-to Maturity Securities, Before Tax Statement of Financial Position [Abstract] Assets: Assets [Abstract] Cash and due from banks Cash and Due from Banks Interest bearing deposits with banks Interest-bearing Deposits in Banks and Other Financial Institutions Federal funds sold and securities purchased under agreements to resell Federal Funds Sold and Securities Purchased under Agreements to Resell Securities available-for-sale Available-for-sale Securities Securities held-to-maturity (fair value of $14.8 billion and $13.7 billion at September 30, 2015 and December 31, 2014, respectively) Held-to-maturity Securities Less – allowance for credit losses Loans, net Loans and Leases Receivable, Net Amount Loans held for sale (includes $175 million and $384 million designated under fair value option at September 30, 2015 and December 31, 2014, respectively) Properties and equipment, net Property, Plant and Equipment, Net Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Other assets Other Assets Total assets Assets Liabilities Liabilities [Abstract] Domestic deposits: Deposits, Domestic [Abstract] Noninterest bearing Noninterest-bearing Deposit Liabilities, Domestic Interest bearing (includes $6.5 billion and $7.3 billion designated under fair value option at September 30, 2015 and December 31, 2014, respectively) Interest-bearing Deposit Liabilities, Domestic Foreign deposits: Deposits, Foreign [Abstract] Noninterest bearing Noninterest-bearing Deposit Liabilities, Foreign Interest bearing Interest-bearing Deposit Liabilities, Foreign Total deposits Deposits Short-term borrowings (includes $2.1 billion designated under fair value option at September 30, 2015) Short-term Debt Long-term debt (includes $8.6 billion and $8.8 billion designated under fair value option at September 30, 2015 and December 31, 2014, respectively) Long-term Debt Total debt Debt and Capital Lease Obligations Interest, taxes and other liabilities Other Liabilities Total liabilities Liabilities Shareholders’ equity Stockholders' Equity Attributable to Parent [Abstract] Preferred stock Preferred Stock, Value, Issued Common shareholder’s equity: Common Shareholders Equity [Abstract] Common Shareholders Equity Abstract. Common stock ($5 par; 150,000,000 shares authorized; 714 and 713 shares issued and outstanding at September 30, 2015 and December 31, 2014, respectively) Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss Total common shareholders' equity Stockholders' Equity Attributable to Parent, Attributable to Common Stockholders Stockholders' Equity Attributable to Parent, Attributable to Common Stockholders Total shareholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and shareholders’ equity Liabilities and Equity Guarantee Arrangements, Pledged Assets and Collateral Commitments and Contingencies Disclosure [Text Block] Residential Mortgage Loan Nonaccrual Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell Residential Mortgage Loan Nonaccrual Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell Residential Mortgage Loan Nonaccrual Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell Interest income that would have been recorded if the nonaccrual receivable had been current in accordance with contractual terms during the period Loans and Leases Receivable, Impaired, Interest Recorded and Interest Lost on Nonaccrual Loans Loans and Leases Receivable, Impaired, Interest Recorded and Interest Lost on Nonaccrual Loans Interest income that was recorded on nonaccrual loans and included in interest income during the period Interest Income Recorded on Nonaccrual Receivables Interest Income Recorded on Nonaccrual Receivables Loss Contingencies [Table] Loss Contingencies [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] HSBC Bank USA [Member] HSBC Bank USA [Member] HSBC Bank USA [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Weller, et. al. v. HSBC Mortgage Services Inc., et. al. [Member] Weller, et. al. v. HSBC Mortgage Services Inc., et. al. [Member] Weller, et. al. v. HSBC Mortgage Services Inc., et. al. [Member] Credit Default Swaps Antitrust Litigation [Member] Credit Default Swaps Antitrust Litigation [Member] Credit Default Swaps Antitrust Litigation [Member] Foreign Exchange Class Action [Member] Foreign Exchange Class Action [Member] Foreign Exchange Class Action [Member] Saber Ahmed v. HSBC Bank USA [Member] Saber Ahmed v. HSBC Bank USA [Member] Saber Ahmed v. HSBC Bank USA [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Estimate of loss Loss Contingency, Estimate of Possible Loss Damages sought, per violation (up to) Loss Contingency, Damages Sought, Value Litigation settlement amount Litigation Settlement, Amount Number of putative class action complaints filed Loss Contingency, New Claims Filed, Number Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Federal Home Loan Mortgage Corporation [Member] Federal Home Loan Mortgage Corporation [Member] Federal Home Loan Mortgage Corporation [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Obligation to Repurchase Receivables Sold [Member] Obligation to Repurchase Receivables Sold [Member] Outstanding repurchase demands Outstanding Repurchase Demands Outstanding repurchase demands. Estimated Repurchase Liability For Loans Sold [Roll Forward] Estimated Repurchase Liability For Loans Sold [Roll Forward] Estimated Repurchase Liability For Loans Sold [Roll Forward] Balance at beginning of period Loss Contingency Accrual Increase (decrease) in liability recorded through earnings Loss Contingency Accrual, Provision Realized losses Loss Contingency Accrual, Payments Balance at end of period Release of repurchase reserves Loss Contingency Accrual, Period Increase (Decrease) Range of possible losses in excess of recorded repurchase liability, minimum Loss Contingency, Range of Possible Loss, Minimum Range of possible losses in excess of recorded repurchase liability, maximum Loss Contingency, Range of Possible Loss, Maximum Loans Held for Sale Loans Held For Sale Disclosure [Text Block] Loans held for sale. Asset backed securities with changes to other than temporary impairment estimates related to credit component Asset Backed Securities With Changes to Other Than Temporary Impairment Estimates Related to Credit Component Asset Backed Securities With Changes to Other Than Temporary Impairment Estimates Related to Credit Component Increase in credit losses for which an other-than-temporary impairment was previously recognized Assets backed securities in available for sale portfolio Assets Backed Securities In Available For Sale Portfolio Assets backed securities in available for sale portfolio. Assets backed securities wrapped by monoline insurance company Assets Backed Securities Wrapped By Insurance Company Assets backed securities wrapped by insurance company. Value of asset backed securities backed by insurance company Value Of Asset Backed Securities Backed By Insurance Company Value of Asset backed securities backed by insurance company. Fair value of asset backed securities Mortgage-backed Securities Available-for-sale, Fair Value Disclosure Available-for-sale securities, backed by insurance company, accumulated unrecognized holding loss Available-for-sale Securities, Backed by Insurance Company, Accumulated Unrecognized Holding Loss Available-for-sale Securities, Backed by Insurance Company, Accumulated Unrecognized Holding Loss Fair value of financial guarantee Other Than Temporary Impairment With Fair Value From Financial Guarantee From Insurance Company Other than temporary impairment with a Fair value from financial guarantee from insurance company. Federal Home Loan Bank Stock Federal Home Loan Bank Stock Federal Reserve Bank Stock Federal Reserve Bank Stock Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Tax (benefit) expense included in net unrealized gains (losses) Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Tax included in reclassification Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Tax included in amortization Other Comprehensive Income (Loss), Amortization of Unrealized Loss on Transfers from Available-for-Sale to Held-to Maturity Securities, Tax Other Comprehensive Income (Loss), Amortization of Unrealized Loss on Transfers from Available-for-Sale to Held-to Maturity Securities, Tax Tax included in reclassification due to accretion Other than Temporary Impairment Losses, Investments, Reclassification Adjustment of Noncredit Portion, Tax, Held-to-maturity Securities Other than Temporary Impairment Losses, Investments, Reclassification Adjustment of Noncredit Portion, Tax, Held-to-maturity Securities Tax (benefit) expense included in net unrealized gains (losses) Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax Tax included in reclassification Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Tax (benefit) included in change in unfunded pension postretirement liability (less than $1 million) Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax Internal Investment Grade [Member] Internal Investment Grade [Member] Internal Noninvestment Grade [Member] Internal Noninvestment Grade [Member] Fair Value Measurements, Recurring, Valuation Techniques [Table] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Recurring [Member] Fair Value, Measurements, Recurring [Member] Broker quotes or consensus pricing and, where applicable, discounted cash flows [Member] Broker Quotes Or Consensus Pricing And Where Applicable Discounted Cash Flows [Member] Broker quotes or consensus pricing and, where applicable, discounted cash flows. Discounted cash flows [Member] Discounted Cash Flows [Member] Discounted cash flows. Market comparable adjusted for probability to fund [Member] Market Comparable Adjusted For Probability To Fund [Member] Market comparable adjusted for probability to fund. Fair Value Measurements, Recurring, Valuation Techniques [Line Items] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Assets, Fair Value Disclosure, Recurring Liabilities, Fair Value Disclosure, Recurring Fair Value Inputs, Prepayment Rate Fair Value Inputs, Prepayment Rate Fair Value Inputs, Probability of Default Fair Value Inputs, Probability of Default Fair Value Inputs, Spread Volatility on Collateral Assets Fair Value Inputs, Spread Volatility on Collateral Assets Fair Value Inputs, Spread Volatility on Collateral Assets Fair Value Inputs, Correlation Between Insurance Claim Shortfall and Collateral Value Fair Value Inputs, Correlation Between Insurance Claim Shortfall and Collateral Value Fair Value Inputs, Correlation Between Insurance Claim Shortfall and Collateral Value Fair Value Inputs, Correlations of Default Among a Portfolio of Credit Names of Embedded Credit Derivatives Fair Value Inputs, Correlations of Default Among a Portfolio of Credit Names of Embedded Credit Derivatives Fair Value Inputs, Correlations of Default Among a Portfolio of Credit Names of Embedded Credit Derivatives Fair Value Inputs, Probability to Fund for Rate Lock Commitments Fair Value Inputs, Probability to Fund for Rate Lock Commitments Fair Value Inputs, Probability to Fund for Rate Lock Commitments Fair Value Inputs, Correlation of Defaults of Portfolio of Reference Credit Names Fair Value Inputs, Correlation of Defaults of Portfolio of Reference Credit Names Fair Value Inputs, Correlation of Defaults of Portfolio of Reference Credit Names Fair Value Inputs, Issuer by Issuer Correlation of Defaults Fair Value Inputs, Issuer by Issuer Correlation of Defaults Fair Value Inputs, Issuer by Issuer Correlation of Defaults Fair Value Inputs, Option Adjusted Spread Fair Value Inputs, Option Adjusted Spread Fair Value Inputs, Option Adjusted Spread Fair Value Inputs, Estimated Annualized Costs to Service Fair Value Inputs, Estimated Annualized Costs to Service Fair Value Inputs, Estimated Annualized Costs to Service Trading Assets and Liabilities Trading Assets And Liability Disclosure [Text Block] Trading assets and liability. Sell-protection credit derivative positions [Member] Buy-protection credit derivative positions [Member] Buy Protection Credit Derivatives [Member] Buy Protection Credit Derivatives [Member] Carrying/Fair Value Carrying/Fair Value Credit Risk Derivative Assets, at Fair Value Net position, Carrying/Fair Value Credit Risk Derivatives, at Fair Value, Net Notional Credit Derivative, Maximum Exposure, Undiscounted Available-for-sale amount within one year Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis Available-for-sale yield within one year Available For Sale Securities Debt Maturities Within One Year Yield Percentage Available for sale securities debt maturities within one year yield percentage. Available-for-sale amount after one but within five years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis Available-for-sale yield after one but within five years Available For Sale Securities Debt Maturities After One Through Five Year Yield Percentage Available for sale securities debt maturities after one through five year yield percentage. Available-for-sale amount after five but within ten years Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis Available-for-sale yield after five but within ten years Available For Sale Securities Debt Maturities After Five Through Ten Years Yield Percentage Available for sale securities debt maturities after five through ten years yield percentage. Available-for-sale amount after ten years Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis Available-for-sale yield after ten years Available For Sale Securities Debt Maturities After Ten Years Amortized Cost Yield Percentage Available for sale securities debt maturities after ten years amortized cost yield percentage. Total fair value within one year Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Total fair value after one but within five years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value Total fair value after five but within ten years Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value Total fair value after ten years Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value Held-to-maturity amount within one year Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount Held-to-maturity yield within one year Held To Maturity Securities Debt Maturities Next Twelve Months Yield Held to maturity securities debt maturities next twelve months yield. Held-to-maturity amount after one but within five years Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount Held-to-maturity yield after one but within five years Held To Maturity Securities Debt Maturities After One But Within Five Years Yield Held to maturity securities debt maturities after one but within five years yield. Held-to-maturity after five but within ten years Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount Held-to-maturity yield after five but within ten years Held To Maturity Securities After Five But Within Ten Years Yield Held to maturity securities after five but within ten years yield. Held-to-maturity after ten years Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount Held-to-maturity yield after ten years Held To Maturity Securities After Ten Years Yield Held to maturity securities after ten years yield. Total fair value within one year Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value Total fair value after one but within five years Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value Total fair value after five but within ten years Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value Total fair value after ten years Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value Assets: Securities purchased under agreements to resell Liabilities: Deposits Short-term borrowings Long-term debt Other Nonaccrual Loans Held-for-sale [Member] Disposal Group, Held-for-sale, Not Discontinued Operations [Member] Total nonaccruing loans Financing Receivable, Recorded Investment, Nonaccrual Status Total accruing loans contractually past due 90 days or more Total nonperforming loans Loans And Leases Impaired Nonperforming Accrual And Nonaccrual Loans And Leases Impaired Nonperforming Accrual And Nonaccrual Fair Value, Option, Quantitative Disclosures Fair Value, Option, Quantitative Disclosures [Table Text Block] Components of Gain on Instruments at Fair Value and Related Derivatives Components Of Gain On Instruments At Fair Value And Related Derivatives Table [Table Text Block] Components Of Gain On Instruments At Fair Value And Related Derivatives Table [Table Text Block] Schedule of Available-for-sale and Held-to-maturity Securities [Table] Schedule of Available-for-sale and Held-to-maturity Securities [Table] Schedule of Available-for-sale and Held-to-maturity Securities [Table] Mortgage-backed securities [Member] Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Collateralized mortgage obligations [Member] Collateralized Mortgage Obligations, Issued by U.S. Government Sponsored Enterprises [Member] Collateralized Mortgage Obligations, Issued by U.S. Government Sponsored Enterprises [Member] Direct agency obligations [Member] Direct Agency Obligations U S Government Sponsored Enterprises [Member] Direct agency obligations US government sponsored enterprises. Mortgage-backed securities, issued or guaranteed by US Government agency [Member] Mortgage-backed Securities, Issued or Guaranteed by US Government Agency [Member] Mortgage-backed Securities, Issued or Guaranteed by US Government Agency [Member] Collateralized mortgage obligations, issued or guaranteed by US Government agency [Member] Collateralized Mortgage Obligations, Issued or Guaranteed by US Government Agency [Member] Collateralized Mortgage Obligations, Issued or Guaranteed by US Government Agency [Member] Foreign Government [Member] Foreign Government [Member] Foreign Government [Member] Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member] Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member] Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items] Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items] Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items] Amortized Cost, Available-for-sale securities Available-for-sale Securities, Amortized Cost Basis Unrealized Gains, Available-for-sale securities Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Unrealized Losses, Available-for-sale securities Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Fair Value, Available-for-sale securities Amortized Cost, Held-to-Maturity Securities Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment Unrealized Gains, Held-to-maturity securities Held-to-maturity Securities, Accumulated Unrecognized Holding Gain Unrealized Losses, Held-to-maturity securities Held-to-maturity Securities, Accumulated Unrecognized Holding Loss Held-to-maturity Securities, Fair Value Held-to-maturity Securities, Fair Value Components of Loans Components Of Loans [Table Text Block] Components Of Loans [Table Text Block] Summary of Past Due Status of Loans Past Due Financing Receivables [Table Text Block] Summary of Nonaccrual Loans and Accruing Receivables 90 Days or More Delinquent Schedule of Financing Receivables, Non Accrual Status [Table Text Block] Schedule of Additional Information on Nonaccrual Loans Schedule of Additional Information on Nonaccrual Loans [Table Text Block] Schedule of Additional Information on Nonaccrual Loans [Table Text Block] Summary of Receivables which were Modified and as a Result Became Classified as TDR Loans Receivables Classified As Trouble Debt Restructuring Loans [Table Text Block] Receivables Classified As Trouble Debt Restructuring Loans [Table Text Block] Summary of TDR and Related Credit Loss Reserves for TDR Loans Troubled Debt Restructurings on Financing Receivables [Table Text Block] Trouble Debt Restructuring Additional Information Trouble Debt Restructuring Additional Information [Table Text Block] Trouble Debt Restructuring Additional Information [Table Text Block] Loans Classified as TDR Loans Commercial Loans Classified As Trouble Debt Restructuring Loans Table [Table Text Block] Commercial Loans Classified As Trouble Debt Restructuring Loans Table [Table Text Block] Impaired Commercial Loans Considered as TDR Loans Impaired Commercial Loans Considered As Trouble Debt Restructuring Loans [Table Text Block] Impaired Commercial Loans Considered As Trouble Debt Restructuring Loans [Table Text Block] Average Balance and Interest Income Recognized on Impaired Commercial Loans Average Balance And Interest Income Recognized On Impaired Commercial Loans [Table Text Block] Average Balance And Interest Income Recognized On Impaired Commercial Loans [Table Text Block] Summary of Criticized Assets for Commercial Loans Financing Receivable Credit Quality Indicators [Table Text Block] Status of Commercial Loan Portfolio Financing Receivable Credit Quality Indicators Related To Nonperforming [Table Text Block] Financing Receivable Credit Quality Indicators Related To Nonperforming [Table Text Block] Credit Risk Profile of Commercial Loan Financing Receivable Credit Quality Indicators Related To Credit Risk Profile [Table Text Block] Financing Receivable Credit Quality Indicators Related To Credit Risk Profile [Table Text Block] Delinquency Ratio for Consumer Loan Delinquency Ratio For Consumer Loan [Table Text Block] Delinquency Ratio For Consumer Loan [Table Text Block] Status of Consumer Loan Portfolio Consumer Loan Portfolio [Table Text Block] Consumer Loan Portfolio [Table Text Block] Compensation and Retirement Disclosure [Abstract] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] HSBC North America Pension Plan [Member] Pension Plan [Member] Postretirement Plans Other Than Pensions [Member] Other Postretirement Benefit Plan [Member] Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Components of Net Periodic Benefit Cost Schedule of Net Benefit Costs [Table Text Block] Fair Value Option Fair Value, Option [Text Block] Fair Value Measurements, Nonrecurring [Table] Impaired Consumer Loans [Member] Impaired Consumer Loans [Member] Impaired Consumer Loans [Member] Commercial Loans Held for Sale [Member] Commercial Loans Held for Sale [Member] Commercial Loans Held for Sale [Member] Impaired commercial loans [Member] Impaired Commercial Loans [Member] Impaired Commercial Loans Real Estate Owned [Member] Real Estate [Member] Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items] Assets, Fair Value Disclosure, Nonrecurring Assets, Fair Value Disclosure, Nonrecurring Total Gains (Losses) Fair Value Assets Measured On Non Recurring Basis Gain Loss Included In Revenue Fair value assets measured on non recurring basis gain loss included in revenue. Total intangible assets Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Nonaccrual loans Fair Value, Option, Loans Held as Assets, Aggregate Amount in Nonaccrual Status Nonaccrual loans, unpaid principal balance Fair Value, Option, Loans Held as Assets, Aggregate Amount in Nonaccrual Status, Unpaid Principal Balance Fair Value, Option, Loans Held as Assets, Aggregate Amount in Nonaccrual Status, Unpaid Principal Balance Accruing loans contractually past due 90 days or more Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due Loans Held for Sale Loans Held For Sale Table [Table Text Block] Loans Held For Sale Table [Table Text Block] Securities Securities Disclosure [Text Block] Securities. Carrying Value and Estimated Fair Value of Financial Instruments Carrying Value And Estimated Fair Value Of Financial Instruments Table [Table Text Block] Carrying Value And Estimated Fair Value Of Financial Instruments Table [Table Text Block] Assets and Liabilities Recorded at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Changes in Fair Value of Level 3 Assets and Liabilities Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Quantitative Information about Recurring Fair Value Measurement of Assets and Liabilities Classified as Level 3 Fair Value Inputs, Assets, Quantitative Information [Table Text Block] Fair Value Hierarchy Level within Which Fair Value of Financial and Non-Financial Assets has been Recorded Fair Value Measurements, Nonrecurring [Table Text Block] Quantitative Information about Non Recurring Fair Value Measurement of Assets and Liabilities Quantitative Information About Non Recurring Fair Value Measurement Of Assets And Liabilities Table [Table Text Block] Quantitative Information About Non Recurring Fair Value Measurement Of Assets And Liabilities Table [Table Text Block] Additional Information Relating to Asset-Backed Securities and Collateralized Debt Obligations Additional Information Relating To Asset Backed Securities And Collateralized Debt Obligations Table [Table Text Block] Additional Information Relating To Asset Backed Securities And Collateralized Debt Obligations Table [Table Text Block] Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Transaction Type [Axis] Transaction Type [Axis] Transaction [Domain] Transaction [Domain] OTC Cleared [Member] OTC Cleared [Member] Over-the-counter (“OTC”) cleared derivatives include privately negotiated derivative contracts that are cleared and settled through central clearing counterparties. Bilateral OTC [Member] Bilateral OTC [Member] Bilateral OTC derivatives include derivatives executed and settled bilaterally with counterparties without the use of an organized exchange or central clearing house. Exchange Traded [Member] Exchange Traded [Member] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Fair Value Hedging [Member] Fair Value Hedging [Member] Cash Flow Hedging [Member] Cash Flow Hedging [Member] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument [Member] Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Interest taxes and other liabilities [Member] Interest Taxes And Other Liabilities [Member] Interest, taxes and other liabilities. Derivative assets Derivative Asset, Fair Value, Gross Asset Derivative liabilities Derivative Liability, Fair Value, Gross Liability Netting assets Netting liabilities Less: Gross amounts of cash collateral received subject to enforceable master netting agreements(5)(6) Less: Gross amounts of cash collateral posted subject to enforceable master netting agreements(5)(6) Derivative Asset Derivative Liability Less: Gross amounts of financial instrument collateral received not offset Derivative Asset, Fair Value, Amount Offset Against Collateral Less: Gross amounts of financial instrument collateral posted not offset Derivative Liability, Fair Value, Amount Offset Against Collateral Net amount of derivative asset Derivative Asset Net Represents the amount of derivative assets net of assets that does not meet applicable offsetting guidance and cash and non-cash collateral under master netting arrangements. Net amount of derivative liability Derivative Liability Net Represents the amount of derivative liabilities net of liabilities that does not meet applicable offsetting guidance and cash and non-cash collateral under master netting arrangements. Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) [Table] Interest Income (Expense), Net [Member] Interest Income (Expense), Net [Member] Interest Income (Expense), Net [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Gain (Loss) Recognized in AOCI on Derivative (Effective Portion) Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net Gain (Loss) Reclassed From AOCI into Income (Effective Portion) Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Gain (Loss) Recognized in Income on the Derivative (Ineffective Portion) Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net Amount with Impairment Reserves Impaired Financing Receivable, with Related Allowance, Recorded Investment Amount without Impairment Reserves Impaired Financing Receivable, with No Related Allowance, Recorded Investment Total Impaired Commercial Loans Impaired Financing Receivable, Recorded Investment Impairment Reserve Impaired Financing Receivable, Related Allowance Unpaid principal balance of impaired commercial loans Impaired Financing Receivable, Unpaid Principal Balance Securities held-to-maturity, fair value Loans Held-for-sale, designated under fair value option Common stock, par value (usd per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (shares) Common Stock, Shares Authorized Common stock, shares issued (shares) Common Stock, Shares, Issued Common stock, shares outstanding (shares) Common Stock, Shares, Outstanding Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Hsbc North America [Member] Hsbc North America [Member] HSBC North America. Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Service cost – benefits earned during the period Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return on Plan Assets Amortization of net actuarial (gain) loss Defined Benefit Plan, Amortization of Gains (Losses) Net periodic benefit cost Defined Benefit Plan, Net Periodic Benefit Cost Contributions by employer Defined Benefit Plan, Contributions by Employer Fair Value, Measurements, Nonrecurring [Member] Fair Value, Measurements, Nonrecurring [Member] Third Party Appraisal [Member] Third Party Appraisal [Member] Third party appraisal. Total average balance of impaired commercial loans Impaired Financing Receivable, Average Recorded Investment Total interest income recognized on impaired commercial loans Impaired Financing Receivable, Interest Income, Accrual Method Retained Earnings and Regulatory Capital Requirements Regulatory Capital Requirements under Banking Regulations [Text Block] Alt [Member] Alt [Member] Alt-A. Residential Mortgages [Member] Student loans [Member] Commercial mortgages [Member] Home Equity [Member] Other [Member] Credit Rating Source [Axis] Credit Rating Source [Axis] Credit Rating Source [Domain] Credit Rating Source [Domain] AAA - A Rating [Member] Aaaa Rating [Member] AAA-A Rating. BBB -B Rating [Member] Bbbb Rating [Member] BBB-B Rating. CCC - Unrated [Member] Ccc Unrated [Member] CCC-Unrated. Trading Securities [Member] Available-for-sale Securities [Member] Fair Value Of Other Financial Instrument [Line Items] Fair Value Of Other Financial Instrument [Line Items] Fair Value Of Other Financial Instrument [Line Items] Trading asset-backed securities and related collateral Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value Interest income: Interest and Dividend Income, Operating [Abstract] Loans Interest and Fee Income, Loans and Leases Securities Interest Income Securities Interest income on securities classified either as available-for-sale or held-to-maturity and includes: (a) interest and dividends earned on all securities and (b) amortization and accretion (as applicable) of discounts and premiums, if any. Excludes trading securities. Trading securities Interest and Dividend Income, Securities, Operating, Trading or Measured at Fair Value Short-term investments Interest Income Short Term Investments Interest income on from federal funds and deposits with other financial institutions and includes: (a) interest and dividends earned and (b) amortization and accretion (as applicable) of discounts and premiums, if any. Other Other Interest and Dividend Income Total interest income Interest expense: Interest Expense [Abstract] Deposits Interest Expense, Deposits Short-term borrowings Interest Expense, Short-term Borrowings Long-term debt Interest Expense, Long-term Debt Other Interest Expense, Other Total interest expense Net interest income after provision for credit losses Interest Income (Expense), after Provision for Loan Loss Other revenues: Noninterest Income [Abstract] Credit card fees Fees and Commissions, Credit Cards Trust and investment management fees Fees and Commissions, Fiduciary and Trust Activities Other fees and commissions Fees and Commissions, Other Net other-than-temporary impairment losses Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net Other securities gains, net Gain (Loss) on Sale of Securities, Net Servicing and other fees from HSBC affiliates Residential mortgage banking revenue Residential Mortgage Banking Revenue Loss The noninterest income derived from mortgage banking activities (fees and commissions) as well as fees earned from servicing third-party assets. Other income Other Income Total other revenues Noninterest Income Operating expenses: Noninterest Expense [Abstract] Salaries and employee benefits Labor and Related Expense Support services from HSBC affiliates Occupancy expense, net Occupancy, Net Other expenses Other Noninterest Expense Total operating expenses Noninterest Expense Income (loss) before income tax Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income tax expense (benefit) Income Tax Expense (Benefit) Net income Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] RBWM [Member] Rbwm [Member] RBWM. CMB [Member] Cmb [Member] CMB. GBM [Member] Gbm [Member] GBM. PB [Member] Pb [Member] PB. Other [Member] Other Segments [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Group Reporting Basis Adjustments [Member] Group Reporting Basis Adjustments [Member] Group Reporting Basis Adjustments [Member] Group Reporting Basis Reclassifications [Member] Group Reporting Basis Reclassifications [Member] Group Reporting Basis Reclassifications [Member] Aggregate [Member] Aggregate [Member] Aggregate. Operating Segments [Member] Operating Segments [Member] Segment Reconciling Items [Member] Segment Reconciling Items [Member] Operating Statistics [Line Items] Operating Statistics [Line Items] Operating Statistics [Line Items ] Group Reporting Basis Net interest income Group Reporting Basis Net Interest Income (Expense) Group Reporting Basis Net Interest Income (Expense) Group Reporting Basis Other operating income Group Reporting Basis Non Interest Income (Expense) Group Reporting Basis Non Interest Income (Expense) Group Reporting Basis Total operating income Group Reporting Basis Operating Income Group Reporting Basis Operating Income Group Reporting Basis Loan impairment charges Group Reporting Basis Loan Impairment Charges (Recoveries) Group Reporting Basis Loan Impairment Charges (Recoveries) Group Reporting Basis Revenues Group Reporting Basis Operating Income Net Group Reporting Basis Operating Income Net Group Reporting Basis Operating expenses Group Reporting Basis Operating Expense (Income) Group Reporting Basis Operating Expense (Income) Group Reporting Basis Income (loss) from continuing operations before income tax Group Reporting Basis Profit (Loss) Before Income Tax Expense Group Reporting Basis Profit (Loss) Before Income Tax Expense Group Reporting Basis Total assets Group Reporting Basis Assets Group Reporting Basis Assets Group Reporting Basis Total loans, net Group Reporting Basis Loans And Leases Receivable Net Reported Amount Group Reporting Basis Loans And Leases Receivable Net Reported Amount Group Reporting Basis Goodwill Group Reporting Basis Goodwill Group Reporting Basis Goodwill Group Reporting Basis Total deposits Group Reporting Basis Deposits Group Reporting Basis Deposits Net interest income Other operating income Total operating income Operating Income (Loss) Loan impairment charges Total income Revenues Operating expenses Total assets Total loans, net Goodwill Total deposits Group Reporting Basis Brokered Deposits Group Reporting Basis Deposits, Brokered Deposits Group Reporting Basis Deposits, Brokered Deposits Mortgage Securitization Activity Related Litigation [Member] Mortgage Securitization Activity Related Litigation [Member] Mortgage securitization activity related litigation. Debt Security Category [Axis] Debt Security Category [Axis] Major Types of Debt and Equity Securities [Domain] Other than Temporary Impairment, Credit Losses Recognized in Earnings, Categories of Investments [Domain] Hsbc Securities [Member] Hsbc Securities [Member] HSBC Securities. Guarantor Obligations, Maximum Exposure, Undiscounted Allowance for credit losses on unfunded standby letters of credit Allowance For Credit Losses On Unfunded Standby Letters Of Credit Allowance for credit losses on unfunded standby letters of credit. Whole loan securitization Related Party, Whole Loan Securitization Program, Amounts of Transaction Related Party, Whole Loan Securitization Program, Amounts of Transaction Mortgage Securitization Outstanding Loan Purchase And Sold Mortgage Securitization Outstanding Loan Purchase And Sold Mortgage securitization outstanding loan purchase and sold. Securities pledged as collateral that can be sold or repledged by the secured party, fair value Financial Instruments Owned and Pledged as Collateral, Amount Eligible to be Repledged by Counterparty Collateral accepted under security resale agreements, fair value Securities Purchased under Agreements to Resell, Fair Value of Collateral Collateral accepted under security repurchase agreements but not reported on the balance sheet that can be sold or repledged, fair value Customer Securities for which Entity has Right to Sell or Repledge, Fair Value Collateral accepted under security repurchase agreements that has been sold or repledged under repurchase agreements or to cover short sales Customer Securities for which Entity has Right to Sell or Repledge, Fair Value of Securities Sold or Repledged Outstanding Repurchase Demands Related Party Transactions Related Party Transactions Disclosure [Text Block] Fair Value Hierarchy Fair Value Measurement, Policy [Policy Text Block] Goodwill Goodwill Disclosure [Text Block] Number of Reportable Segments Number of Reportable Segments Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Junior Subordinated Debentures Issued to HSBC USA Capital Trust I [Member] Junior Subordinated Debentures Issued to Entity One [Member] Junior Subordinated Debentures Issued to Entity One [Member] Junior Subordinated Debentures Issued to HSBC USA Capital Trust II [Member] Junior Subordinated Debentures Issued to Entity Two [Member] Junior Subordinated Debentures Issued to Entity Two [Member] Junior Subordinated Debentures Issued to HSBC USA Capital Trust III [Member] Junior Subordinated Debentures Issued to Entity Three [Member] Junior Subordinated Debentures Issued to Entity Three [Member] Junior Subordinated Debentures [Member] Junior Subordinated Debt [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Noncumulative Preferred Stock [Member] Noncumulative Preferred Stock [Member] Adjustable Rate Cumulative Preferred Stock, Series D [Member] Adjustable Rate Cumulative Preferred Stock, Series D [Member] Adjustable Rate Cumulative Preferred Stock, Series D [Member] $2.8575 Cumulative Preferred Stock [Member] Cumulative Preferred Stock [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock [Member] Common Stock [Member] HSBC Bank USA, National Association [Member] Subsidiaries [Member] HSBC USA Inc [Member] Parent Company [Member] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Repayments of Long-term Debt Repayments of Long-term Debt Contributions Proceeds from Contributions from Parent Distributions Payments For Distributions To Subsidiary Payments From Distributions To Subsidiary Number of shares of common stock issued to parent Stock Issued During Period, Shares, New Issues Junior subordinated debentures called during the period Debt Instrument, Repurchased Face Amount Contractual call price (percent) Debt Instrument, Redemption Price, Percentage Loss on extinguishment of debentures Gains (Losses) on Extinguishment of Debt Dividend per share (usd per share) Preferred Stock, Dividend Rate, Per-Dollar-Amount Preferred stock, redemption price per share (usd per share) Preferred Stock, Redemption Price Per Share Payments for repurchase of redeemable preferred stock Payments for Repurchase of Redeemable Preferred Stock Statement of Stockholders' Equity [Abstract] Preferred Stock [Member] Preferred Stock [Member] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] Retained Earnings [Member] Accumulated Other Comprehensive Loss [Member] AOCI Attributable to Parent [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance at beginning of period Balance at beginning of period Preferred stock redemption Stock Redeemed or Called During Period, Value Capital contribution from parent Stock Issued During Period, Value, New Issues Employee benefit plans Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Cash dividends declared on preferred stock Dividends, Preferred Stock, Cash Other comprehensive income (loss), net of tax Balance at end of period Balance at end of period Total Modified Receivable Of Troubled Debt Restructuring Loans Modified receivable of troubled debt restructuring loans. Amortized Cost and Fair Value of the Securities Available-for-Sale and Held-to-Maturity Amortized Cost And Fair Value Of Securities Available For Sale And Held To Maturity Table [Table Text Block] Amortized Cost And Fair Value Of Securities Available For Sale And Held To Maturity Table [Table Text Block] Gross Unrealized Losses and Related Fair Values Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block] Other than Temporary Impairment, Credit Losses Recognized in Earnings Other than Temporary Impairment, Credit Losses Recognized in Earnings [Table Text Block] Realized Gains and Losses on Investment Securities Transactions Attributable to Available-for-Sale Securities Schedule of Realized Gain (Loss) [Table Text Block] Distribution of Maturities of Debt Securities with the Approximate Yield of the Portfolio Investments Classified by Contractual Maturity Date [Table Text Block] Interest only residential mortgage loans Interest Only Residential Mortgage Loans Interest only residential mortgage loans. Interest Income [Member] Interest Income [Member] Interest Expense [Member] Interest Expense [Member] Interest Income Expense [Member] Interest Income Expense [Member] Interest income (expense). Gain (Loss) on Derivative Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments Gain (Loss) on Hedged Items Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge Net Ineffective Gain (Loss) Recognized - Other Income Gain (Loss) on Fair Value Hedge Ineffectiveness, Net Total capital ratio: Capital [Abstract] Capital Amount Capital Well-Capitalized Ratio Capital Required to be Well Capitalized to Risk Weighted Assets Actual Ratio, Total Capital Capital to Risk Weighted Assets Tier 1 capital ratio: Tier One Risk Based Capital [Abstract] Capital Amount, Tier 1 capital Tier One Risk Based Capital Well-Capitalized Ratio, Tier 1 capital Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets Actual Ratio, Tier 1 Capital Tier One Risk Based Capital to Risk Weighted Assets Common equity Tier 1 ratio: Tier One Common Ratio [Abstract] Tier one common ratio. Capital Amount, Common Equity Tier 1 Capital Under Common Equity Tier One, Basel III. Capital Under Common Equity Tier One, Basel III. Well Capitalized Ratio Common equity Tier 1 Well Capitalized Minimum Ratio Common Equity Tier 1 Well Capitalized Minimum Ratio Common Equity Tier 1 Actual Ratio Common equity Tier 1 Actual Ratio Common Equity Tier 1 Actual Ratio Common Equity Tier 1 Tier 1 leverage ratio: Leverage Ratios [Abstract] Capital Amount, Tier 1 leverage capital Tier One Leverage Capital Well-Capitalized Ratio, Tier 1 leverage capital Tier One Leverage Capital Required to be Well Capitalized to Average Assets Actual Ratio, Tier 1 leverage capital Tier One Leverage Capital to Average Assets Risk weighted assets: Risk Based Ratios [Abstract] Risk Weighted Assets Risk Weighted Assets Trading revenue [Member] Trading Revenue [Member] Amount of Gain (Loss) Recognized in Income on Derivatives Gain (Loss) on Derivative Instruments Held for Trading Purposes, Net Pension and Other Postretirement Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Interest bearing deposits with banks Pledged Assets Not Separately Reported Interest Bearing Deposits With Banks Pledged assets not separately reported interest bearing deposits with banks. Trading assets Pledged Assets Not Separately Reported Trading Assets Pledged assets not separately reported trading assets. Securities available-for-sale Pledged Financial Instruments, Not Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment Securities held to maturity Pledged Financial Instruments, Not Separately Reported, Other Debt Securities Held-to-maturity Loans Pledged Financial Instruments, Not Separately Reported, Loans Receivable Pledged as Collateral Other assets Pledged Assets, Not Separately Reported, Other Total Pledged Assets, Other, Not Separately Reported on Statement of Financial Position Delinquent Loans Financing Receivable Recorded Investment Equal To Greater Than Sixty Days Past Due Financing Receivable Recorded Investment Equal To Greater Than Sixty Days Past Due Delinquency Ratio Loans and Leases Receivable, Ratio of Nonperforming Loans to All Loans Statement of Cash Flows [Abstract] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Amortization and Accretion, Net Other-than-temporary impairment related to securities held-to-maturity Other than Temporary Impairment Losses, Investments Net realized gains on securities available-for-sale Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments Net change in other assets and liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net Net change in loans held for sale: Increase (Decrease) in Loans Held-for-sale [Abstract] Originations and purchases of loans held for sale Payments for Origination and Purchases of Loans Held-for-sale Sales and collections of loans held for sale Proceeds from Sale and Collection of Loans Held-for-sale Net change in trading assets and liabilities Increase (Decrease) in Trading Assets and Liabilities, Net Increase (Decrease) in Trading Assets and Liabilities, Net Lower of amortized cost or fair value adjustments on loans held for sale Other Noncash Income (Expense) Loss (gain) on instruments designated at fair value and related derivatives Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Net change in interest bearing deposits with banks Proceeds from (Payments for) in Interest-bearing Deposits in Banks Net change in federal funds sold and securities purchased under agreements to resell Proceeds from (Payments for) Federal Funds Sold and Securities Purchased under Agreements to Resell, Net Securities available-for-sale: Securities Available For Sale [Abstract] Securities available for sale. Purchases of securities available-for-sale Payments to Acquire Available-for-sale Securities Proceeds from sales of securities available-for-sale Proceeds from Sale of Available-for-sale Securities Proceeds from maturities of securities available-for-sale Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Securities held-to-maturity: Proceeds from Sale and Maturity of Held-to-maturity Securities [Abstract] Purchases of securities held-to-maturity Payments to Acquire Held-to-maturity Securities Proceeds from maturities of securities held-to-maturity Proceeds from Maturities, Prepayments and Calls of Held-to-maturity Securities Change in loans: Change In Loans [Abstract] Change In Loans Abstract Originations, net of collections Proceeds from Loan and Lease Originations and Principal Collections Loans sold to third parties Proceeds from Sale of Loans Held-for-investment Net cash used for acquisitions of properties and equipment Payments for (Proceeds from) Productive Assets Other, net Payments for (Proceeds from) Other Investing Activities Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Net change in deposits Increase (Decrease) in Deposits Debt: Proceeds from (Repayments of) Debt [Abstract] Net change in short-term borrowings Proceeds from (Repayments of) Short-term Debt Issuance of long-term debt Proceeds from Issuance of Long-term Debt Repayment of long-term debt Preferred stock redemption Capital contribution from parent Other decreases in capital surplus Proceeds from (Payments for) Other Financing Activities Dividends paid Payments of Ordinary Dividends, Preferred Stock and Preference Stock Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Net change in cash and due from banks Cash and Cash Equivalents, Period Increase (Decrease) Cash and due from banks at beginning of period Cash and due from banks at end of period Schedule of Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Fair Value of Residential MSRs Schedule Of Critical Assumptions Used To Calculate Fair Value Of Residential Mortgage Servicing Rights Table [Table Text Block] Schedule Of Critical Assumptions Used To Calculate Fair Value Of Residential Mortgage Servicing Rights Table [Table Text Block] Residential MSRs Activity Schedule of Servicing Assets at Fair Value [Table Text Block] Other loans included in impaired loans apart from TDR loans Other Impaired Commercial Loan Other impaired commercial loan. Residential Mortgage Loan TDR Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell Non Accrual loans included in TDR loan Trouble Debt Restructuring Non Accrual Loan Trouble debt restructuring non accrual loan. Carrying Value of TDR Loans Unpaid Principal Balance of TDR Loans Unpaid Principal Balance Of Troubled Debt Securities Loans Unpaid principal balance of troubled debt securities loans. Allowance for credit losses on TDR Loans Financing Receivable Modification Allowance For Credit Losses Financing receivable modification allowance for credit losses.