Equity [Abstract] Units Outstanding Units Outstanding [Text Block] The entire disclosure of an entity's capital units or capitals shares outstanding. Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Components of Deferred Sales Commissions Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block] Expected Amortization of Deferred Sales Commissions Schedule of Amortization of Deferred Sales Commissions Future Amortization Expense [Table Text Block] Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for amortization of deferred sales commissions. Retirement Benefits [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Retirement Plan [Member] Pension Plan [Member] Defined Benefit Plan, Asset Categories [Axis] Defined Benefit Plan, Asset Categories [Axis] Plan Asset Categories [Domain] Plan Asset Categories [Domain] Equity Securities [Member] Equity Securities [Member] Debt Securities [Member] Debt Securities [Member] Other [Member] Cash and Cash Equivalents [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined benefit plan, actual plan asset allocations, percent Defined Benefit Plan, Actual Plan Asset Allocations Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative [Table] Derivative [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Exchange-Traded Future [Member] Foreign Exchange Future [Member] Currency Forwards [Member] Foreign Exchange Forward [Member] Interest Rate Swap [Member] Interest Rate Swap [Member] Credit Default Swap [Member] Credit Default Swap [Member] Option Swap [Member] Swap [Member] Total Return Swap [Member] Total Return Swap [Member] Derivative [Line Items] Derivative [Line Items] Notional Value Derivative, Notional Amount Derivative Assets Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value Derivative Liabilities Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value Gains (Losses) Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] AXA and its subsidiaries [Member] AXA And Its Subsidiaries [Member] International group of insurance and related financial services companies and certain other subsidiaries. Related Party Transaction [Line Items] Related Party Transaction [Line Items] Revenues: Revenues [Abstract] Investment advisory and services fees Investment Advisory Fees Bernstein research services Brokerage Commissions Revenue Distribution revenues Fees and Commissions, Other Other revenues Revenue, Other Financial Services Total revenues Revenues Expenses: Operating Expenses [Abstract] Commissions and distribution payments to financial intermediaries Noninterest Expense Distribution and Servicing Fees General and administrative General and Administrative Expense Other Floor Brokerage, Exchange and Clearance Fees Total expenses Costs and Expenses Balance Sheet: Statement of Financial Position [Abstract] Institutional investment advisory and services fees receivable Accrued Fees and Other Revenue Receivable Prepaid expenses Prepaid Insurance Other due to AXA and its subsidiaries Related Party Transaction, Due from (to) Related Party Total Institutional investment advisory and services fees receivable Net Total carrying value as of the balance sheet date of Institutional investment advisory fees, services fees receivables, and other receivables (payables) to be collected from (obligations owed to) related parties, net as of the balance sheet date. Valuation and Qualifying Accounts [Abstract] Valuation and Qualifying Accounts - Allowance for Doubtful Accounts Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Retired Individual Plan [Member] Supplemental Employee Retirement Plan [Member] Foreign Retirement Plans [Member] Other Postretirement Benefits Plan [Member] Recognized actuarial (loss) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Amortization of prior service cost Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Changes in employee benefit related items Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax Income tax expense Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax Employee benefit related items, net of tax Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax Statement [Table] Statement [Table] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] VIEs Consolidated [Member] Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member] Statement [Line Items] Statement [Line Items] ASSETS Assets [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value, Excluding Variable Interest Entities Cash and Cash Equivalents, at Carrying Value, Excluding Variable Interest Entities Cash and securities segregated, at fair value (cost $816,350 and $946,093) Cash and Securities Segregated under Federal and Other Regulations Receivables, net: Receivables, Net, Current [Abstract] Brokers and dealers Receivables from Brokers-Dealers and Clearing Organizations Brokerage clients Receivables from Customers Due from Related Parties Due from Related Parties Other fees Investments: Investments [Abstract] Long-term incentive compensation-related Financial Instruments, Owned, at Fair Value Other Financial Instruments, Owned, Other, at Fair Value Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Investments Investments Other assets Other Assets Furniture, equipment and leasehold improvements, net Property, Plant and Equipment, Net Goodwill Goodwill Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Deferred sales commissions, net Deferred Sales Commission Total assets Assets LIABILITIES AND CAPITAL LIABILITIES AND CAPITAL ABSTRACT [Abstract] Liabilities: Liabilities [Abstract] Payables: Payables and Accruals [Abstract] Brokers and dealers Payables to Broker-Dealers and Clearing Organizations Securities sold not yet purchased Financial Instruments Sold, Not yet Purchased, at Fair Value Brokerage clients Payables to Customers AB mutual funds Due to Related Parties Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities Liabilities of consolidated company-sponsored investment funds Variable Interest Entity, Consolidated, Carrying Amount, Liabilities Accrued compensation and benefits Employee-related Liabilities Debt Short-term Debt Total liabilities Liabilities Commitments and contingencies (See Note 13) Commitments and Contingencies Redeemable non-controlling interest Redeemable Noncontrolling Interest, Equity, Carrying Amount Capital: Capital [Abstract] General Partner General Partners' Capital Account Limited partners: 268,659,333 and 268,893,534 units issued and outstanding Limited Partners' Capital Account Receivables from affiliates Capital contributions receivable from affiliates Amounts due from affiliates of the reporting entity related to the capital contributions during the period. AB Holding Units held for long-term incentive compensation plans Deferred Compensation Equity Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Partners’ capital attributable to AB Unitholders Partners' Capital Non-redeemable non-controlling interests in consolidated entities Partners' Capital Attributable to Noncontrolling Interest Total capital Partners' Capital, Including Portion Attributable to Noncontrolling Interest Total liabilities and capital Liabilities and Equity Expected future benefit payments [Abstract] Defined Benefit Plan, Expected Future Benefit Payment [Abstract] 2018 Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months 2019 Defined Benefit Plan, Expected Future Benefit Payment, Year Two 2020 Defined Benefit Plan, Expected Future Benefit Payment, Year Three 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Four 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Five 2023-2027 Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter Fair Value Disclosures [Abstract] Fair Value of Assets and Liabilities Measured on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Fair Value Measurement Level 3 Reconciliation Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Schedule of Contingent Payment Arrangements Level 3 Financial Instruments Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Consolidated Company-Sponsored Investment Funds [Abstract] Consolidated Company-Sponsored Investment Funds [Abstract] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Variable Interest Entity, Primary Beneficiary [Member] Variable Interest Entity, Primary Beneficiary [Member] VOEs [Member] Voting Interest Entities [Member] Voting Interest Entities [Member] Derivative Asset [Abstract] Derivative Asset [Abstract] Gross Amounts of Recognized Assets Derivative Asset, Fair Value, Gross Asset Gross Amounts Offset in the Statement of Financial Condition Derivative Asset, Fair Value, Gross Liability Net Amounts of Assets Presented in the Statement of Financial Condition Derivative Asset Financial Instruments Derivative, Collateral, Obligation to Return Securities Cash Collateral Received Derivative, Collateral, Obligation to Return Cash Net Amount Derivative Asset, Fair Value, Amount Offset Against Collateral Derivative Liability [Abstract] Derivative Liability [Abstract] Gross Amounts of Recognized Liabilities Derivative Liability, Fair Value, Gross Liability Gross Amounts Offset in the Statement of Financial Condition Derivative Liability, Fair Value, Gross Asset Net Amounts of Liabilities Presented in the Statement of Financial Condition Derivative Liability Financial Instruments Derivative, Collateral, Right to Reclaim Securities Cash Collateral Pledged Derivative Liability, Collateral, Right to Reclaim Cash, Offset Net Amount Derivative Liability, Fair Value, Amount Offset Against Collateral Investments, Debt and Equity Securities [Abstract] Investment Holdings [Table] Investment Holdings [Table] Investment Secondary Categorization [Axis] Investment Secondary Categorization [Axis] Investments by Secondary Categorization [Domain] Investments by Secondary Categorization [Domain] Seed Capital [Member] Seed Capital [Member] Seed money which is provided to investment teams to develop new products and services. Investment Holdings [Line Items] Investment Holdings [Line Items] Investments owned Investment Owned, at Fair Value Proceeds from sales of available-for-sale investments Proceeds from Sale of Available-for-sale Securities Realized gains from sales of available-for-sale investments Available-for-sale Securities, Gross Realized Gains Realized losses from sale of available-for-sale investments Available-for-sale Securities, Gross Realized Losses Related Party Transactions Related Party Transactions Disclosure [Text Block] Offsetting [Abstract] Offsetting of Financial Assets Offsetting Assets [Table Text Block] Offsetting of Financial Liabilities Offsetting Liabilities [Table Text Block] Cash and securities segregated, at cost Cash And Securities Segregated At Cost Amount of cash subject to withdrawal restrictions, restricted deposits held as compensating balances, and cash and securities segregated in compliance with regulations (such as cash deposited in a special reserve account for the exclusive benefit of customers pursuant). LIABILITIES AND CAPITAL Liabilities and Equity [Abstract] Capital: Limited partners units issued (in units) Limited Partners' Capital Account, Units Issued Limited partners, units outstanding (in units) Limited Partners' Capital Account, Units Outstanding 2018 Deferred Sales Commission Future Amortization Expense Year One The amount of amortization expense expected to be recognized during year one of the six succeeding fiscal years. 2019 Deferred Sales Commission Future Amortization Expense Year Two The amount of amortization expense expected to be recognized during year two of the six succeeding fiscal years. 2020 Deferred Sales Commission Future Amortization Expense Year Three The amount of amortization expense expected to be recognized during year three of the six succeeding fiscal years. 2021 Deferred Sales Commission Future Amortization Expense Year Four The amount of amortization expense expected to be recognized during year four of the six succeeding fiscal years. 2022 Deferred Sales Commission Future Amortization Expense Year Five The amount of amortization expense expected to be recognized during year five of the six succeeding fiscal years. 2023 Deferred Sales Commission Future Amortization Expense Year Six The amount of amortization expense expected to be recognized during year six of the six succeeding fiscal years. Total Deferred Sales Commissions Future Amortization Expense The aggregate estimated amortization expense for succeeding fiscal years for deferred sales commissions subject to amortization. Property, Plant and Equipment [Abstract] Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment by Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Furniture and Equipment [Member] Furniture and Fixtures [Member] Leasehold Improvements [Member] Leasehold Improvements [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Furniture, equipment and leasehold improvements [Abstract] Property, Plant and Equipment, Net, by Type [Abstract] Furniture, equipment and leasehold improvements, gross Property, Plant and Equipment, Gross Less: Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Furniture, equipment and leasehold improvements, net Organization, Consolidation and Presentation of Financial Statements [Abstract] Business Description and Organization Nature of Operations [Text Block] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Interest cost on projected benefit obligations Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Amortization of prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Recognized actuarial loss Defined Benefit Plan, Amortization of Gain (Loss) Net pension (benefit) expense Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Income Tax Disclosure [Abstract] Effective Income Tax Rate Reconciliation, Amount [Abstract] Effective Income Tax Rate Reconciliation, Amount [Abstract] UBT statutory rate Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Corporate subsidiaries’ federal, state, local and foreign income taxes Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount 2017 federal tax reform enactment Effective Income Tax Rate Reconciliation, Tax Cuts And Jobs Act Of 2017, Amount Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act of 2017, Amount Effect of ASC 740 adjustments, miscellaneous taxes, and other Effective Income Tax Rate Reconciliation, Tax Contingency, Amount Income not taxable resulting from use of UBT business apportionment factors Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount Income tax expense Income Tax Expense (Benefit) Effective Income Tax Rate Reconciliation, Percent [Abstract] Effective Income Tax Rate Reconciliation, Percent [Abstract] UBT statutory rate, percent Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Corporate subsidiaries’ federal, state, local and foreign income taxes, percent Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent 2017 federal tax reform enactment, percent Effective Income Tax Rate Reconciliation, Tax Cuts And Jobs Act Of 2017, Percent Effective Income Tax Rate Reconciliation, Tax Cuts And Jobs Act Of 2017, Percent Effect of ASC 740 adjustments, miscellaneous taxes, and other, percent Effective Income Tax Rate Reconciliation, Tax Contingency, Percent Income not taxable resulting from use of UBT business apportionment factors, percent Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent Effective tax rate, percent Effective Income Tax Rate Reconciliation, Percent Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Foreign Tax Authority [Member] Foreign Tax Authority [Member] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Valuation allowance Deferred Tax Assets, Valuation Allowance NOL carryforwards Operating Loss Carryforwards Distributions Made to Limited Partner [Table] Distributions Made to Limited Partner [Table] Limited Partnership Interest By Partner [Axis] Limited Partnership Interest By Partner [Axis] Pertinent data on partners in a limited partnership. Limited Partnership Interest Partners [Domain] Limited Partnership Interest Partners [Domain] Partners in a limited partnership. AB Holding [Member] Holdings [Member] Represents the holding Company, AllianceBernstein Holdings, that has an ownership interest in Company. Unaffiliated holders [Member] Unaffiliated Holders [Member] Represents holders of ownership interest in Company that are otherwise unaffiliated with Company. Distribution Made to Limited Partner [Line Items] Distribution Made to Limited Partner [Line Items] Ownership structure of AB Holding Limited Liability Company or Limited Partnership, Summary of Ownership Structure [Abstract] Limited partners or members ownership interest in Company (percent) Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Brokers and Dealers [Abstract] United States Treasury Bills in special reserve bank custody account for exclusive benefit of brokerage customers of SCB LLC Cash and Securities Segregated under Securities Exchange Commission Regulation Restricted funds held for benefit of customers by AB Investments, Inc. Restricted Cash and Cash Equivalents Changes in Units Outstanding Schedule of Capital Units [Table Text Block] Segment Reporting [Abstract] Net Revenues From Investment Management, Research and Related Services Revenue from External Customers by Products and Services [Table Text Block] Net Revenues and Long-Lived Assets, Related to Geographic Areas Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block] Unrecognized net loss from experience different from that assumed and effects of changes and assumptions Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax Prior service cost Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax Pension and other postretirement benefit plans, accumulated other comprehensive loss, before tax Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax Income tax benefit Accumulated Other Comprehensive Income Loss Tax Effect Tax effect on the accumulated change in equity from transactions and other events and circumstances from non-owner sources. Accumulated other comprehensive loss Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax 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] Balance as of beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value Addition Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Accretion Accretion (Amortization) of Discounts and Premiums, Investments Changes in estimates Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Increase (Decrease) in Estimates Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Increase (Decrease) in Estimates Payments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales Balance as of end of period Commitments and Contingencies Disclosure [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Venture Capital Funds [Member] Venture Capital Funds [Member] Real Estate Fund [Member] Real Estate Fund [Member] Represents the real estate fund. Real Estate Fund II [Member] Real Estate Fund II [Member] Represents the real estate fund II. Oil and gas fund [Member] Oil and gas fund [Member] Represents the oil and gas fund. Loss Contingencies [Line Items] Loss Contingencies [Line Items] Other [Abstract] Other [Abstract] Committed total required invest funding Unrecorded Unconditional Purchase Obligation Commitment agreement fundings Unrecorded Unconditional Purchase Obligation, Purchases Accounting Policies [Abstract] Collateralized Securities Transactions [Abstract] Financial Instruments Owned and Pledged as Collateral [Abstract] Cash on deposit with clearing organizations for trade facilitation purposes Margin Deposit Assets SCB LLC held U.S. Treasury Bills Security Owned and Pledged as Collateral, Fair Value Investments [Abstract] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Consolidated Private Equity Fund [Member] Consolidated Private Equity Fund [Member] Consolidated investments held in private equity. Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Ownership percentage Equity Method Investment, Ownership Percentage Private equity investments owned outside of consolidated venture capital fund Private equity investments owned outside of consolidated venture capital fund The number of private equity investments owned by an entity outside of previously disclosed consolidated venture capital fund Equipment and software [Table] Furniture [Member] Equipment [Member] Equipment [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Furniture, Equipment and Leasehold Improvements [Abstract] Useful Life Property, Plant and Equipment, Useful Life Deferred Sales Commissions, Net [Abstract] Period of time the deferred sales commissions are amortized over for U.S. fund shares Deferred Sales Commission Amortization Period Us Fund Remaining amortization period for any deferred sales commission related to US Funds. Period of time the deferred sales commissions are amortized over for non-U.S. fund shares Deferred Sales Commission Amortization Period Non Us Funds Remaining amortization period for any deferred sales commission related to non-US Funds. Mutual Fund Underwriting Activities [Abstract] Mutual Fund Underwriting Activities [Abstract] Period over which receivables from brokers and dealers for sale of shares of company-sponsored mutual funds generally are realized Period over which receivables from brokers and dealers for sale of shares of company-sponsored mutual funds generally are realized Represents the period over which receivables from brokers and dealers for sale of shares of company-sponsored mutual funds generally are realized. Schedule of Deferred Compensation Arrangement with Individual, Share-based Payments [Table] Schedule of Deferred Compensation Arrangement with Individual, Share-based Payments [Table] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Employees Based Outside of the United States [Member] Employees Based Outside of the United States [Member] The award for employees based outside of the U.S. Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] Long-term Incentive Compensation Plans [Abstract] Compensation Related Costs [Abstract] Employee allocation percentage maximum, percent Maximum percentage of award an employee can elect to allocate to deferred cash Maximum percentage of award that an employee can elect to allocate to deferred cash. Long-term incentive cash maximum per employee Maximum amount of deferred cash Maximum amount of deferred cash an employee can elect to allocate under the plan. Long-term incentive awards vesting periods Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period AB Holding Units purchased in periods (in units) Stock Repurchased During Period, Shares Dollar amount paid for AB Holding Units acquired Stock Repurchased During Period, Value Open-market purchases of AB Holding Units (in units) Share-based Compensation Arrangement by Share-based Payment Award, Shares Purchased for Award Dollar amount paid for open-market purchases of AB Holding Units Payments for Repurchase of Equity Restricted AB Holding Units awarded to employees (in units) Stock Issued During Period, Shares, Share-based Compensation, Gross Units issued upon exercise of options (in units) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Proceeds from stock options exercised Proceeds from Stock Options Exercised Foreign Currency Translations [Abstract] Foreign Currency Transaction [Abstract] Net foreign currency transaction gains (losses) Foreign Currency Transaction Gain (Loss), Realized Cash Distributions [Abstract] Distributions Made to Members or Limited Partners [Abstract] Subsequent Event [Table] Subsequent Event [Table] Statement, Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Partners' Capital attributable to AB Unitholders [Member] Parent [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Distribution Type [Axis] Distribution Type [Axis] Distribution Type [Domain] Distribution Type [Domain] Cash Distribution [Member] Cash Distribution [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2014-09 [Member] Accounting Standards Update 2014-09 [Member] Cash Distribution [Line Items] Cumulative effect of ASU adoption Cumulative Effect of New Accounting Principle in Period of Adoption Cash distribution, declaration date Distribution Made to Limited Partner, Declaration Date Cash distribution, distribution declared (in dollars per unit) Distribution Made to Limited Partner, Distributions Declared, Per Unit Percentage of General Partnership interest in company Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest Cash distribution, distribution date Distribution Made to Limited Partner, Distribution Date Cash distribution, date of record Distribution Made to Limited Partner, Date of Record Cash distributions per unit paid to the General Partner and Unitholders (in dollars per unit) Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Paid Quarterly Financial Data [Abstract] Net revenues Revenues, Net of Interest Expense Net income attributable to AB Unitholders Net Income (Loss) Attributable to Parent Basic net income per AB Unit (in dollars per unit) Net Income (Loss), Per Outstanding Limited Partnership Unit, Basic, Net of Tax Diluted net income per AB Unit (in dollars per unit) Net Income (Loss), Net of Tax, Per Outstanding Limited Partnership Unit, Diluted Cash distributions per AB Unit (in dollars per unit) Quarterly Financial Data Quarterly Financial Information [Table Text Block] Risks and Uncertainties [Abstract] Counterparty Risk Concentration Risk Disclosure [Text Block] Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Unrecognized net (loss) gain from experience different from that assumed and effects of changes and assumptions Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, before Tax Prior service cost Income tax expense Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile net income to net cash provided by operating activities: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Amortization of deferred sales commissions Amortization of Deferred Sales Commissions Non-cash long-term incentive compensation expense Share-based Compensation Depreciation and other amortization Depreciation, Amortization and Accretion, Net Unrealized losses (gains) on investments Marketable Securities, Unrealized Gain (Loss) Losses on real estate asset write-offs Gain (Loss) on Sale of Assets and Asset Impairment Charges Other, net Other Noncash Income (Expense) Changes in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Consolidation of cash and cash equivalents of consolidated company-sponsored investment funds Consolidation of VIE Cash and Cash Equivalents Consolidation of VIE's Cash and Cash Equivalents Decrease (increase) in segregated cash and securities Increase (Decrease) in Restricted Investments for Operating Activities Decrease (increase) in receivables Increase (Decrease) in Receivables Decrease in investments Increase (Decrease) in Financial Instruments Used in Operating Activities Decrease (increase) in deferred sales commissions Increase (Decrease) in Deferred Charges (Increase) decrease in other assets Increase (Decrease) in Other Operating Assets (Decrease) increase in payables Increase (Decrease) in Other Accounts Payable Increase (decrease) in accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Increase (decrease) in accrued compensation and benefits Increase (Decrease) in Employee Related Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of investments Payments to Acquire Available-for-sale Securities Proceeds from sales of investments Purchases of furniture, equipment and leasehold improvements Payments to Acquire Property, Plant, and Equipment Proceeds from sales of furniture, equipment and leasehold improvements Proceeds from Sale of Property, Plant, and Equipment Purchase of intangible asset Payments to Acquire Intangible Assets Purchase of businesses, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] (Repayment) issuance of commercial paper, net Proceeds from (Repayments of) Short-term Debt Proceeds from bank loans Proceeds from Lines of Credit Increase (decrease) in overdrafts payable Proceeds from (Repayments of) Bank Overdrafts Distributions to General Partner and Unitholders Payments of Ordinary Dividends, Common Stock Purchases (redemptions) of non-controlling interests of consolidated company-sponsored investment funds, net Proceeds from (Payments to) Noncontrolling Interests Purchase of non-controlling interest Payments to Noncontrolling Interests Capital contributions from affiliates Proceeds from Contributions from Affiliates Payments of contingent payment arrangements/purchase of shares Repayments of Other Debt Additional investments by AB Holding with proceeds from exercise of compensatory options to buy AB Holding Units Purchases of AB Holding Units to fund long-term incentive compensation plan awards, net Payments for Repurchase of Other Equity Purchases of AB Units Payments for Repurchase of Common Stock Other Proceeds from (Payments for) Other Financing Activities Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Effect of exchange rate changes on cash and cash equivalents Effect of Exchange Rate on Cash and Cash Equivalents Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents as of beginning of the period Cash and cash equivalents as of beginning of the period Postconfirmation, Cash and Cash Equivalents Cash and cash equivalents as of end of the period Cash paid: Cash Paid [Abstract] Interest paid Interest Paid Income taxes paid Income Taxes Paid Non-cash investing activities: Cash Flow, Noncash Investing Activities Disclosure [Abstract] Fair value of assets acquired Fair Value of Assets Acquired Fair value of liabilities assumed Liabilities Assumed Fair value of redeemable non-controlling interest recorded Redeemable Noncontrolling Interest, Equity, Fair Value Non-cash financing activities: Non-cash Financing activities: [Abstract] Payables recorded under contingent payment arrangements Business Combination, Contingent Consideration, Liability Debt Disclosure [Abstract] Debt Debt Disclosure [Text Block] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Capital Accumulation Plan [Member] Capital Accumulation Plan [Member] Capital Accumulation Plan [Member] AllianceBernstein Venture Fund I, L.P. [Member] AllianceBernstein Venture Fund I, L.P. [Member] Entity created by parent company in the form of a limited partnership to achieve capital appreciation through equity and equity-related investments. Sales of company-sponsored mutual funds Mutual Fund Sales By Affiliate Amount of sales of company sponsored mutual funds by an affiliate during the period. Other investments Awards granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Term over which payments are to be received Share-based Compensation Arrangement by Share-based Payment Award, Payments To Be Received, Term Share-based Compensation Arrangement by Share-based Payment Award, Payments To Be Received, Term General Partners Contribution to long-term incentive compensation plan Partners' Capital Account, Contributions Net receivable balance Receivables, Net, Current Noncontrolling Interest [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Company-Sponsored Investment Funds [Member] Consolidated Investment Portfolios [Member] Consolidated Investment Portfolios [Member] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Consolidated Private Equity Fund [Member] Private Equity Funds [Member] Other Investments [Member] Other Investments [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] CPH Acquisition [Member] CPH Acquisition [Member] CPH acquisition Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Non-redeemable non-controlling interests Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest Redeemable non-controlling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Net income of consolidated entities attributable to non-controlling interests Net Income (Loss) Attributable to Noncontrolling Interest Non-redeemable non-controlling interest Restructuring and Related Activities [Abstract] Real Estate Liability Account Activity Related to Workforce Reduction Schedule of Restructuring Reserve by Type of Cost [Table Text Block] Net Capital Brokers and Dealers Disclosure [Text Block] Furniture, Equipment and Leasehold Improvement, Net Property, Plant and Equipment [Table Text Block] Deferred tax asset: Components of Deferred Tax Assets [Abstract] Benefits from net operating loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards Long-term incentive compensation plans Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation Investment basis differences/net unrealized losses Deferred Tax Assets, Other Comprehensive Loss Depreciation and amortization Deferred Tax Assets, Depreciation and Amortization Deferred Tax Assets, Depreciation and Amortization Other, primarily accrued expenses deductible when paid Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Deferred tax assets, gross Deferred Tax Assets, Gross Less: valuation allowance Deferred tax asset Deferred Tax Assets, Net of Valuation Allowance Deferred tax liability: Components of Deferred Tax Liabilities [Abstract] Intangible assets Deferred Tax Liabilities, Intangible Assets Other Deferred Tax Liabilities, Other Deferred tax liability Deferred Tax Liabilities, Net Net deferred tax asset Deferred Tax Assets, Net Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Cash and Securities Segregated Under Federal Regulations and Other Requirements Restricted Assets Disclosure [Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Private Equity Funds [Member] 2010 Acquisition [Member] Two Thousand Ten Acquisition [Member] Two Thousand Ten Acquisition [Member] 2013 Acquisition [Member] Two Thousand Thirteen Acquisition [Member] Two Thousand Thirteen Acquisition [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Contingent Consideration by Type [Axis] Contingent Consideration by Type [Axis] Contingent Consideration Type [Domain] Contingent Consideration Type [Domain] Contingent Payment Arrangements [Member] Contingent Payment Arrangements [Member] Contingent Payment Arrangements [Member] Weighted Average [Member] Weighted Average [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Private Equity Investment Venture Capital Fund [Member] Private Equity Investment Venture Capital Fund [Member] Private equity investment in a venture capital fund investing in a communications consumer, digital media, healthcare and information technology markets. Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair value of private equity investment Alternative Investment, Fair Value Disclosure Fair value of investment Investments, Fair Value Disclosure Contingent payment arrangements Additional amount per share shareholders are entitled to if the assets under management exceed the threshold (in dollars per unit) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Contingent Value Rights, Additional Amount Per Share Shareholders Are Entitled To Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Additional Amount Per Share Shareholders Are Entitled To Assets under management threshold Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Contingent Value Rights, Assets Under Management Threshold Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Contingent Value Rights, Assets Under Management Threshold Number of businesses acquired Number of Businesses Acquired AUM growth rates weighted average Fair Value Inputs Assets Under Management Growth Rate Percentage of assumed growth under assets management, used as an input to measure fair value. Revenue growth rate Fair Value Inputs, Long-term Revenue Growth Rate Discount rate Fair Value Inputs, Discount Rate Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Time Deposits [Member] Bank Time Deposits [Member] Limited Partnership Hedge Funds [Member] Hedge Funds [Member] Position [Axis] Position [Axis] Position [Domain] Position [Domain] Long [Member] Long [Member] 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] US Treasury Bills [Member] US Treasury Bill Securities [Member] Fixed Income Securities [Member] Fixed Income Securities [Member] Exchange Traded Options [Member] Exchange Traded Options [Member] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Level 3 [Member] Assets, Fair Value Disclosure [Abstract] Assets, Fair Value Disclosure [Abstract] Money markets Money Market Funds, at Carrying Value Securities segregated (U.S. Treasury Bills) Financial Instruments, Owned, US Government and Agency Obligations, at Fair Value Derivatives Trading Trading Securities [Abstract] Trading securities Trading Securities Private equity Financial Instruments, Owned, Principal Investments, at Fair Value Investments, NAV Expedient Investments, Other Measurements Investments, Measurements Other than Fair Value Investments, Measurements Other than Fair Value Available-for-sale Available-for-sale Securities Total investments Total assets measured at fair value Assets, Fair Value Disclosure Total investments measured at fair value and other measurements Investments, Fair Value Disclosure and Other Measurements Investments, Fair Value Disclosure and Other Measurements Assets, Fair Value Disclosure and Other Measurements Assets, Fair Value Disclosure and Other Measurements Assets, Fair Value Disclosure and Other Measurements Securities sold not yet purchased Liabilities, Fair Value Disclosure [Abstract] Short equities – corporate Trading Liabilities, Fair Value Disclosure Short exchange-traded options Financial Instruments Sold, Not yet Purchased, Derivatives and Other Contracts Derivatives Total liabilities measured at fair value Financial and Nonfinancial Liabilities, Fair Value Disclosure Summary of Derivative Instruments Schedule of Derivative Instruments [Table Text Block] Summary of Investments Investment Holdings, Schedule of Investments [Table Text Block] Summary of the Cost and Fair Value of Available-For-Sale and Trading Investments Unrealized Gain (Loss) on Investments [Table Text Block] Schedule Of Regulatory Capital Agencies And Requirements [Table] Schedule Of Regulatory Capital Agencies And Requirements [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Stanford C. Bernstein & Co.,LLC [Member] Stanford C. Bernstein & Co.,LLC [Member] Wholly-owned subsidiary of AllianceBernstein that provides Bernstein research services in the United States Stanford C. Bernstein Limited [Member] Stanford C. Bernstein Limited [Member] Wholly-owned subsidiary of AllianceBernstein that provides Bernstein research services primarily in Europe. AB Investments [Member] Alliance Bernstein Investments [Member] Wholly-owned subsidiary of AllianceBernstein that services retail clients and distributes company-sponsored mutual funds Regulatory Agencies [Axis] Regulatory Agencies [Axis] Regulatory bodies that establish capital requirements for member brokers and dealers. Regulatory Agencies [Domain] Regulatory Agencies [Domain] List of regulatory agencies. US Securities And Exchange Commission [Member] US Securities And Exchange Commission [Member] Regulatory body which holds primary responsibility for enforcing the federal securities laws and regulating the securities industry, the nation's stock and options exchanges, and other electronic securities markets in the United States. Schedule Of Regulatory Capital Agencies And Requirements [Line Items] Schedule Of Regulatory Capital Agencies And Requirements [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Computation of Net Capital or Financial Resource Requirement [Abstract] Net Capital [Abstract] Minimum net capital required per stock exchange and SEC rules Capital Requirement of Consolidated Broker-Dealer Subsidiary Electing Alternative Method Alternative method of calculating aggregate debit items arising from customer transactions permitted by rule, percent Net Capital Minimum Required Minimum Target Alternate Calculation The percentage under alternative method of calculating the aggregate debit items arising from customer transactions permitted by rule. Rule requires the larger of this percentage or the base minimum amount. Net capital Net Capital Alternative excess net capital Alternative Excess Net Capital Alternative net capital requirement Alternative Net Capital Requirement Minimum financial resources/net capital required Minimum Net Capital Required Actual net capital in excess of the minimum net capital required Excess Capital Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Option Awards [Member] Equity Option [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Fair Value Assumptions and Methodology Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected cash distribution yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Historical volatility factor Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Expected term Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Restricted Stock Units (RSUs) [Member] Restricted Stock Units (RSUs) [Member] AB Holding Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Unvested as of December 31, 2016 (in units) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in units) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (in units) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in units) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Unvested as of December 31, 2017 (in units) Weighted Average Grant Date Fair Value per AB Holding Unit Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Unvested as of December 31, 2016, Weighted Average Grant Date Fair Value per AB Holding Unit (in dollars per unit) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted, Weighted Average Grant Date Fair Value per AB Holding Unit (in dollars per unit) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Vested, Weighted Average Grant Date Fair Value per AB Holding Unit (in dollars per unit) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited, Weighted Average Grant Date Fair Value per AB Holding Unit (in dollars per unit) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Unvested as of December 31, 2017, Weighted Average Grant Date Fair Value per AB Holding Unit (in dollars per unit) Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Qualified Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Furniture, Equipment and Leasehold Improvements, Net Property, Plant and Equipment Disclosure [Text Block] Net gains recognized during the period Net Realized and Unrealized Gain (Loss) on Trading Securities Less: net gains (losses) recognized during the period on trading securities sold during the period Trading Securities, Realized Gain (Loss) Unrealized gains recognized during the period on trading securities held Trading Securities, Change in Unrealized Holding Gain (Loss) Short [Member] Short [Member] Cash collateral received Return of cash collateral into brokerage accounts Derivative, Collateral, Right to Reclaim Cash Long exchange-trade equity options at fair value Short exchange-traded equity options at fair value Losses on equity options activity Gain (Loss) on Derivative Instruments Held for Trading Purposes, Net Payments [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2018 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2019 Operating Leases, Future Minimum Payments, Due in Two Years 2020 Operating Leases, Future Minimum Payments, Due in Three Years 2021 Operating Leases, Future Minimum Payments, Due in Four Years 2022 Operating Leases, Future Minimum Payments, Due in Five Years 2023 and thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total future minimum payments Operating Leases, Future Minimum Payments Due Sublease Receipts [Abstract] Operating Leases, Future Minimum Payments Receivable [Abstract] 2018 Operating Leases, Future Minimum Payments Receivable, Current 2019 Operating Leases, Future Minimum Payments Receivable, in Two Years 2020 Operating Leases, Future Minimum Payments Receivable, in Three Years 2021 Operating Leases, Future Minimum Payments Receivable, in Four Years 2022 Operating Leases, Future Minimum Payments Receivable, in Five Years 2023 and thereafter Operating Leases, Future Minimum Payments Receivable, Thereafter Total future minimum payments receivable Operating Leases, Future Minimum Payments Receivable Net Payments [Abstract] Operating Leases, Future Net Minimum Payments Due [Abstract] 2018 Operating Leases, Future Net Minimum Payments Due, Current For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments, net of future minimum payments receivable, due, within one year of the balance sheet date relating to leases defined as operating. 2019 Operating Leases, Net Future Minimum Payments, Due in Two Years For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments, net of future minimum payments receivable, due within the second year of the balance sheet date relating to leases defined as operating. 2020 Operating Leases, Net Future Minimum Payments, Due in Three Years For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments, net of future minimum payment receivable, due within the third year of the balance sheet date relating to leases defined as operating. 2021 Operating Leases, Net Future Minimum Payments, Due in Four Years For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments, net of future minimum payment receivable, due within the fourth year of the balance sheet date relating to leases defined as operating. 2022 Operating Leases, Net Future Minimum Payments, Due in Five Years For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments, net of future minimum payment receivable, due within the fifth year of the balance sheet date relating to leases defined as operating 2023 and thereafter Operating Leases, Net Future Minimum Payments, Due Thereafter For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments, net of future minimum payment receivable, due after the fifth year from the balance sheet date on leases defined as operating. Total future net minimum payments Operating Leases, Net Future Minimum Payments Due The total of net future contractually required payments on leases defined as operating. Deferred sales commissions [Abstract] Deferred sales commisions [Abstract] Gross to net deferred sales commissions [Abstract] Gross to net deferred sales commissions [Abstract] Carrying amount of deferred sales commissions Deferred Sales Commissions Gross Gross commissions paid to financial intermediaries in connection with the sale of shares of open-end company-sponsored mutual funds sold without a front-end sales charge. These commissions are capitalized as deferred sales commissions and amortized over periods not exceeding five and one-half years for U.S. fund shares and four years for non-U.S. fund shares, the periods of time during which deferred sales commissions are generally recovered. Less: Accumulated amortization Accumulated Amortization of Other Deferred Costs Cumulative CDSC received Cumulative Contingent Deferred Sales Commission Received Cumulative contingent deferred sales commission received as of the balance sheet date. Deferred sales commissions, net Amortization expense Offsetting Assets [Table] Offsetting Assets [Table] Securities Borrowed [Member] Securities Borrowed [Member] The securities borrowed as part of an exchange contract. Derivatives [Member] Commodity Contract [Member] Offsetting Assets [Line Items] Offsetting Assets [Line Items] Securities Borrowed [Abstract] Securities Borrowed [Abstract] Gross Amounts of Recognized Assets Securities Borrowed, Gross Gross Amounts Offset in the Statement of Financial Condition Securities Borrowed, Liability Net Amounts of Assets Presented in the Statement of Financial Condition Securities Borrowed Financial Instruments Securities Borrowed, Collateral, Obligation to Return Securities Cash Collateral Received Securities Borrowed, Collateral, Obligation to Return Cash Net Amount Securities Borrowed, Amount Offset Against Collateral Non-controlling Interest in Net Income Non-controlling Interest in Net Income [Table Text Block] Non-controlling Interest in Net Income [Table Text Block] Non-redeemable Noncontrolling Interest Non-Redeemable Noncontrolling Interest [Table Text Block] Non-Redeemable Noncontrolling Interest [Table Text Block] Redeemable Non-controlling Interest Redeemable Noncontrolling Interest [Table Text Block] Income Tax Examination [Table] Income Tax Examination [Table] Income Tax Authority, Name [Axis] Income Tax Authority, Name [Axis] Income Tax Authority, Name [Domain] Income Tax Authority, Name [Domain] City of New York [Member] City of New York [Member] City of New York [Member] Income Tax Examination [Line Items] Income Tax Examination [Line Items] New York City unincorporated business tax rate New York City unincorporated business tax rate Tax rate attributable to operating income for unincorporated business entities operating in New York City, before credits paid for unincorporated business entities by a subsidiary. Income tax expense for repatriation of foreign earnings Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Income Tax Expense (Benefit) Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Income Tax Expense (Benefit) Income tax expense to reduce deferred tax assets due to lower corporate tax rates Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit) Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit) Interest expense recorded in income tax expense Unrecognized Tax Benefits, Interest on Income Taxes Expense Accrued interest payable recorded on the consolidated statements of financial condition Unrecognized Tax Benefits, Interest on Income Taxes Accrued Accrued penalties recorded on the consolidated statements of financial condition Unrecognized Tax Benefits, Income Tax Penalties Accrued Reductions related to closed years/settlements with tax authorities Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Decrease in accrued interest Unrecognized Tax Benefits, Increase (Decrease) Of Interest on Income Taxes Accrued Unrecognized Tax Benefits, Increase (Decrease) Of Interest on Income Taxes Accrued Minimum years that remain open and may be subject to examination vary under local law Minimum years that remain open and may be subject to examination vary under local law Element represents the minimum number of years that will remain open may be subject to examination vary under local law. Maximum years that remain open and may be subject to examination vary under local law Maximum years that remain open and may be subject to examination vary under local law Element represents the maximum number of years that will remain open may be subject to examination vary under local law. Unrecognized tax benefits Unrecognized Tax Benefits Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Options to Buy AB Holding Units Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Outstanding as of December 31, 2016 (in units) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Granted (in units) Exercised (in units) Forfeited (in units) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Expired (in units) Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Outstanding as of December 31, 2017 (in units) Exercisable as of December 31, 2017, Options to Buy AB Holding Units (in units) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Vested or Expected to Vest as of December 31, 2017, Options to Buy AB Holding Units (in units) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Weighted Average Exercise Price Per Option Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Outstanding as of December 31, 2016, Weighted Average Exercise Price Per Option (in dollars per unit) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Granted, Weighted Average Exercise Price Per Option (in dollars per unit) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Exercised, Weighted Average Exercise Price Per Option (in dollars per unit) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Forfeited, Weighted Average Exercise Price Per Option (in dollars per unit) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Expired, Weighted Average Exercise Price Per Option (in dollars per unit) Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Outstanding as of December 31, 2017, Weighted Average Exercise Price Per Option (in dollars per unit) Exercisable as of December 31, 2017, Weighted Average Exercise Price Per Option (in dollars per unit) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Vested or Expected to Vest as of December 31, 2017, Weighted Average Exercise Price Per Option (in dollars per unit) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Outstanding, Weighted Average Remaining Contractual Term Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Exercisable as of December 31, 2017, Weighted Average Remaining Contractual Term Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Vested and Expected to Vest as of December 31, 2017, Weighted Average Remaining Contractual Term Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Outstanding as of December 31, 2017, Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Exercisable as of December 31, 2017, Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Vested or Expected to Vest as of December 31, 2017, Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Square feet of office space sub-leased Area of Real Estate Property Real estate liability restructuring reserve [Abstract] Restructuring Reserve [Roll Forward] Balance as of January 1, Restructuring Reserve Expense incurred Restructuring Charges Deferred rent Restructuring Reserve, Accrual Adjustment Payments made Payments for Restructuring Interest accretion Accretion Expense Balance as of end of period Change in projected benefit obligation: Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Projected benefit obligation at beginning of year Defined Benefit Plan, Benefit Obligation Interest cost Actuarial loss (gain) Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Projected benefit obligation at end of year Change in plan assets: Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Plan assets at fair value at beginning of year Defined Benefit Plan, Fair Value of Plan Assets Actual return on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Employer contribution Defined Benefit Plan, Plan Assets, Contributions by Employer Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Plan assets at fair value at end of year Funded status Defined Benefit Plan, Funded (Unfunded) Status of Plan Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Defined Benefit Plan by Plan Asset Categories [Axis] Cash [Member] Cash [Member] Fixed Income Mutual Funds [Member] Fixed Income Mutual Funds [Member] Fixed income mutual funds. Equity Mutual Funds [Member] Equity Mutual Funds [Member] Equity mutual funds. Defined Benefit Plan, Fair Value of Plan Assets by Measurement [Axis] Defined Benefit Plan Disclosure [Line Items] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Defined Benefit Plan, Assets [Abstract] Defined Benefit Plan, Assets, Target Allocations [Abstract] Total assets in the fair value hierarchy excluding net asset value investments Defined Benefit Plan, Fair Value of Plan Assets, Excluding Net Asset Value Investments Defined Benefit Plan, Fair Value of Plan Assets, Excluding Net Asset Value Investments Investments measured at net assets value Defined Benefit Plan, Alternative Investments, Fair Value Of Plan Assets Defined Benefit Plan, Alternative Investments, Fair Value Of Plan Assets Total assets measured at fair value Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Institutions [Member] Institutions [Member] Investment management, research and related services - Institutions Retail [Member] Retail [Member] Investment management, research and related services - retail Private Wealth Management [Member] Private Wealth Management [Member] Investment management, research and related services private wealth management. Bernstein Research Services [Member] Bernstein Research Services [Member] Investment management, research and related services - Bernstein research services Other Services [Member] Other Services [Member] Investment management, research and related services - other Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Financial Services Revenue [Abstract] Financial Services Revenue [Abstract] Total revenues Less: Interest expense Interest Expense Net revenues Earnings before income taxes: Results of Operations, Income before Income Taxes [Abstract] United States Income (Loss) from Continuing Operations before Income Taxes, Domestic Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Total Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income tax expense: Income Tax Expense (Benefit), Continuing Operations [Abstract] Partnership UBT Federal Tax On Partnership Gross Business Income The effective tax based on the (gross) business income. Corporate subsidiaries: Corporate subsidiaries: [Abstract] Federal Federal Income Tax Expense (Benefit), Continuing Operations State and local State and Local Income Tax Expense (Benefit), Continuing Operations Foreign Foreign Income Tax Expense (Benefit), Continuing Operations Current tax expense Current Income Tax Expense (Benefit) Deferred tax (benefit) Deferred Income Tax Expense (Benefit) Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair value measurement Level 3 reconciliation [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Balance as of beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Impact of adoption of ASU 2015-02 Prior Period Reclassification Adjustment Deconsolidated funds Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease) Transfers (out) in Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Realized gains (losses), net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Unrealized (losses) gains, net Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Accrued discounts Investment Income, Net, Amortization of Discount and Premium Balance as of end of period Assumptions used to determine net periodic benefit costs [Abstract] Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Discount rate on benefit obligations Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Expected long-term rate of return on plan assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets Future Minimum Payments Under Non-Cancelable Leases, Sublease Commitments and Related Party Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Offsetting Liabilities [Table] Offsetting Liabilities [Table] Securities Loaned [Member] Securities Loaned [Member] Offsetting Liabilities [Line Items] Offsetting Liabilities [Line Items] Securities Loaned [Abstract] Securities Loaned [Abstract] Gross Amounts of Recognized Liabilities Securities Loaned, Gross Gross Amounts Offset in the Statement of Financial Condition Securities Loaned, Asset Net Amounts of Liabilities Presented in the Statement of Financial Condition Securities Loaned Financial Instruments Securities Loaned, Collateral, Right to Reclaim Securities Cash Collateral Pledged Securities Loaned, Collateral, Right to Reclaim Cash Net Amount Securities Loaned, Amount Offset Against Collateral Financial Instruments Cash Collateral Pledged Schedule of Black-Scholes Option Assumptions Valuation Model Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Summary of Option Awards Activity Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable [Table Text Block] Summary of Activity of Unvested Restricted Holding Units Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Document and Entity Information [Abstract] 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 Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Public Float Entity Public Float Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Balances of Consolidated VIEs and VOEs Included In Condensed Consolidated Statements of Financial Condition Condensed Balance Sheet [Table Text Block] Change in Carrying Value Associated with Level 3 Financial Instruments Carried at Fair Value Offsetting of Derivative Assets Offsetting of Derivative Liabilities Earnings Per Share [Abstract] Percentage of Limited Partners interest in Company Limited Liability Company LLC Or Limited Partnership LP Interest The number of units or percentage investment held by the limited partners of the LLC or LP. Net income per unit, basic and diluted [Abstract] Net Income (Loss), Per Outstanding Limited Partnership and General Partnership Unit, Basic and Diluted, Net of Tax [Abstract] Weighted average units outstanding—basic (in units) Weighted Average Limited Partnership Units Outstanding, Basic Dilutive effect of compensatory options to buy AB Holding Units (in units) Weighted Average Number Diluted Limited Partnership Units Outstanding Adjustment Weighted average units outstanding - diluted (in units) Weighted Average Limited Partnership Units Outstanding, Diluted Options excluded from diluted net income per unit computation due to their anti-dilutive effect (in units) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Ownership Interest By Limited Partners Schedule of Other Ownership Interests [Table Text Block] Offsetting Assets and Liabilities Offsetting Assets and Liabilities [Text Block] The entire disclosure for the offsetting assets and liabilities. Fair Value Fair Value Disclosures [Text Block] Depreciation and amortization expense Depreciation, Depletion and Amortization Real estate charges Other Restructuring Costs Change in Projected Benefit Obligation, Fair Value of Plan Assets and Funded Status of Plan Schedule of Changes in Projected Benefit Obligations [Table Text Block] Reconciliation of Amounts Recognized in Other Comprehensive Income for the Retirement Plan Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Amounts Included in Accumulated Other Comprehensive Income (Loss) for the Retirement Plan Defined Benefit Plan Amounts Recognized in Accumulated Other Comprehensive Income [Table Text Block] Tabular disclosure of the net gain (loss) and net prior service cost or credit recognized in accumulated other comprehensive income (loss) for the period for pension plans and/or other employee benefit plans, including unamortized amounts of the net transition asset or obligation. Expected Future Benefit Payments Schedule of Expected Benefit Payments [Table Text Block] Net (Benefit) Expense Under the Retirement Plan Schedule of Net Benefit Costs [Table Text Block] Actuarial Computations Used to Determine Net Periodic Benefit Costs Schedule of Assumptions Used [Table Text Block] Retirement Plan Asset Allocation Schedule of Allocation of Plan Assets [Table Text Block] Valuation of Retirement Plan Assets by Pricing Observability Levels Schedule of Defined Benefit Plans Disclosures [Table Text Block] Schedule of Short-term Debt [Table] Schedule of Short-term Debt [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Credit Facility [Member] Line of Credit [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility [Member] Revolving Credit Facility [Member] Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Commercial Paper [Member] Commercial Paper [Member] Uncommitted Lines of Credit [Member] Uncommited Lines of Credit [Member] SCB LLC [Member] Subsidiaries [Member] Short-term Debt [Line Items] Short-term Debt [Line Items] Short-term debt outstanding Weighted average interest rate Short-term Debt, Weighted Average Interest Rate, at Point in Time Average daily borrowings Short-term Debt, Average Outstanding Amount Weighted average interest rates on average daily borrowings Weighted Average Interest Rates on Average Daily Borrowings Weighted average interest rates on average daily borrowings Credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Incremental increases in principal Line of Credit Facility Incremental increase amount in principal allowed For a Credit Facility with an incremental maximum borrowing capacity, the maximum allowed incremental increase in the Line of Credit amount in principal. Amounts outstanding under credit facility Long-term Line of Credit Interest Rate Line of Credit Facility, Interest Rate at Period End Proceeds from lines of credit Term of debt instrument Debt Instrument, Term Average daily borrowings Line of Credit Facility, Average Outstanding Amount Weighted average interest rate Line of Credit Facility, Interest Rate During Period Number of uncommitted lines of credit Number of uncommitted lines of credit The number of uncommitted lines of credit. Number of financial institutions offering lines of credit Number of financial institutions offering lines of credit The number of financial institutions offering lines of credit. Number of financial institutions with stated limits Number of financial institutions with stated limits The number of financial institutions with stated limits. Rent expense Operating Leases, Rent Expense, Net Sublease income Operating Leases, Income Statement, Sublease Revenue Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Reportable Legal Entities [Member] Reportable Legal Entities [Member] VIEs [Member] Liabilities Partners' capital attributable to AB Unitholders Investments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Schedule of Limited Partners' Capital Account by Class [Table] Schedule of Limited Partners' Capital Account by Class [Table] Limited Partners' Capital Account by Class [Axis] Limited Partners' Capital Account by Class [Axis] Limited Partners' Capital Account, Class [Domain] Limited Partners' Capital Account, Class [Domain] AB Units [Member] Limited Partners Capital Account Units [Member] Limited partner capital units outstanding Limited Partners' Capital Account [Line Items] Limited Partners' Capital Account [Line Items] Changes in Limited Partnership Units Outstanding Increase (Decrease) in Partners' Capital [Roll Forward] Outstanding as of January 1, (in units) Options exercised (in units) Units issued (in units) Stock Issued During Period, Shares, Restricted Stock Award, Gross Units retired (in units) Stock Repurchased and Retired During Period, Shares Outstanding as of December 31, (in units) Earnings Per Unit, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Concentration Risk [Table] Concentration Risk [Table] Concentration Risk by Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Customer Concentration Risk [Member] Customer Concentration Risk [Member] Concentration Risk by Entity [Axis] Concentration Risk by Entity [Axis] Concentration Risk by Entity [Domain] Concentration Risk by Entity [Domain] AllianceBernstein Global High Yield Portfolio [Member] AllianceBernstein Global High Yield Portfolio [Member] An open-end fund incorporated in Luxembourg. AXA Advisors LLC [Member] AXA Advisors LLC [Member] HSBC [Member] HSBC [Member] HSBC [Member] AXA and subsidiaries [Member] AXA and subsidiaries [Member] Concentration Risk [Line Items] Concentration Risk [Line Items] Number of operating segments Number of Operating Segments Percentage of investment advisory and service fees Percentage Of Investment Advisory and Service Fees Generated Percentage of total investment advisory fees recognized during the period. Percentage of net revenues Percentage of net revenues generated Percentage of the total net revenue recognized during the period. Major Customers [Abstract] Major Customers [Abstract] Percentage of open-end mutual fund sales Percentage Of Open End Mutual Fund Sales Percentage of open ended mutual fund sales that companies are responsible. (open ended mutual fund does not have restrictions on the amount of shares the fund will issue) Percentage of total revenues from general and separate accounts of affiliates Percentage of total revenues from general and separate accounts of affiliates Percentage amount of total revenue deriving from affiliated companies general and separate accounts. Percentage of total revenues from unaffiliated customer (more than) Percentage of total revenues from major customer Maximum percentage amount of total revenue deriving from customers other than affiliated clients. Net Income Per Unit Earnings Per Share [Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Principles of Consolidation Consolidation, Policy [Policy Text Block] Reclassifications Reclassification, Policy [Policy Text Block] Recently Adopted Accounting Pronouncements/Accounting Pronouncements Not Yet Adopted New Accounting Pronouncements, Policy [Policy Text Block] Consolidation of Company-Sponsored Investment Funds Consolidation, Variable Interest Entity, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Fees Receivable, Net Receivables, Policy [Policy Text Block] Brokerage Transactions Securities Borrowed and Loaned Policy [Policy Text Block] Investments Investment, Policy [Policy Text Block] Furniture, Equipment and Leasehold Improvements, Net Property, Plant and Equipment, Policy [Policy Text Block] Goodwill Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Intangible Assets, Net Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block] Deferred Sales Commissions, Net Deferred Charges, Policy [Policy Text Block] Loss Contingencies Commitments and Contingencies, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Contingent Payment Arrangements Business Combinations Policy [Policy Text Block] Mutual Fund Underwriting Activities Commissions, Policy [Policy Text Block] Long-term Incentive Compensation Plans Compensation Related Costs, Policy [Policy Text Block] Foreign Currency Translation and Transactions Foreign Currency Transactions and Translations Policy [Policy Text Block] Cash Distributions Stockholders' Equity, Policy [Policy Text Block] Comprehensive Income Comprehensive Income, Policy [Policy Text Block] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Sanford C Bernstein Inc Acquisition [Member] Sanford C Bernstein Inc Acquisition [Member] Acquisition of investment research and management company. Series of Individually Immaterial Business Acquisitions [Member] Series of Individually Immaterial Business Acquisitions [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Goodwill [Abstract] Goodwill on Consolidated Balance Sheet [Abstract] Goodwill acquired during period Goodwill, Acquired During Period Goodwill Number of reportable segments Number of Reportable Segments Number of reporting units Number of Reporting Units Intangible Assets, Net [Abstract] Intangible Assets, Net (Excluding Goodwill) [Abstract] Intangible assets acquired, estimated useful life Finite-Lived Intangible Asset, Useful Life Intangible assets, net of accumulated amortization Finite-lived intangible assets subject to amortization, net Finite-Lived Intangible Assets, Net Indefinite-lived intangible assets not subject to amortization Indefinite-Lived Intangible Assets (Excluding Goodwill) Gross carrying amount of intangible assets Finite-Lived Intangible Assets, Gross Accumulated amortization of intangible assets Finite-Lived Intangible Assets, Accumulated Amortization Amortization expense on intangible assets Amortization of Intangible Assets Future estimated annual amortization expense [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] 2018 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Five Return Seeking Investments [Member] Return Seeking Investments [Member] The investments classified as return seeking. Risk Mitigating Investments [Member] Risk Mitigating Investments [Member] The investments classified as risk mitigating. Diversifying Investments [Member] Diversifying Investments [Member] The investments classified as diversifying. Dynamic Asset Allocation [Member] Dynamic Asset Allocation [Member] Refers to dynamic allocation of assets. Private Investment Trusts Equity Securities [Member] Private Investment Trusts Equity Securities [Member] Investments in equity securities of companies located around the world. Contributions to qualified profit sharing plan Deferred Compensation Arrangement with Individual, Contributions by Employer Defined contribution expense for foreign entities Defined Contribution Plan, Cost Estimated employer contributions in 2018 Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Other comprehensive (loss) gain Discount rate and lump sum interest rates Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Actuarial Gain (Loss) Changes in Discount Rate and Lump Sum Interest rates, before Tax Amount before tax, after reclassification adjustments, of actuarial gain (loss) due to changes in discount rate and lump sum interest rates that has not been recognized in the income statement. Changes in census data Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Actuarial Gain (Loss) Changes In Census Data, Before Tax Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Actuarial Gain (Loss) Changes In Census Data, Before Tax Earnings of plan assets exceeding expectations Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Actuarial Gain (Loss) Changes in Earnings of Plan Assets Exceeding Expectations, before Tax Amount before tax, after reclassification adjustments, of actuarial gain (loss) due to changes in earnings of plan assets exceeding expectations that has not been recognized in the income statement. Actuarial loss Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Actuarial Gain (Loss) Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Actuarial Gain (Loss) Mortality assumption Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Actuarial Gain (Loss) Changes in Mortality Assumption, before Tax Amount before tax, after reclassification adjustments, of actuarial gain (loss) due to changes in mortality assumption that has not been recognized in the income statement. Defined benefit plan, amortization period Defined Benefit Plan, Amortization Period Defined Benefit Plan, Amortization Period Future amortization of prior service cost Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year Loss to be amortized over next fiscal year Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year Accumulated benefit obligation Defined Benefit Plan, Accumulated Benefit Obligation Assumptions used calculating benefit obligation, discount rate, percent Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Target plan asset allocations, percent Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Retirement plan, number of investments Retirement plan, number of investments The number of investments under the retirement plan. Statement of Comprehensive Income [Abstract] Net income Other comprehensive (loss) income: Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent [Abstract] Foreign currency translation adjustments, before reclassification and tax: Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax Less: reclassification adjustment for (losses) gains included in net income upon liquidation Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax Foreign currency translation adjustments, before tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent Income tax expense Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax Foreign currency translation adjustments, net of tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Unrealized gains (losses) on investments: Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent [Abstract] Unrealized gains (losses) arising during period Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Reclassification Adjustments and Tax Less: reclassification adjustment for (losses) gains included in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Changes in unrealized gains (losses) on investments Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax Income tax benefit (expense) Other Comprehensive Income (Loss), Available-for-sale Securities, Tax Unrealized gains (losses) on investments, net of tax Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Changes in employee benefit related items: Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent [Abstract] Recognized actuarial (loss) gain Employee benefit related items, net of tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent Other comprehensive gain (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Less: Comprehensive income in consolidated entities attributable to non-controlling interests Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest Comprehensive income attributable to AB Unitholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Income Taxes Income Tax Disclosure [Text Block] Investments Short equities Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Balance as of beginning of period Additions for prior year tax positions Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Reductions for prior year tax positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Additions for current year tax positions Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Reductions for current year tax positions Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions Reductions related to closed years/settlements with tax authorities Balance as of end of period Award Date [Axis] Award Date [Axis] Award Date [Domain] Award Date [Domain] 2017 Grant 1 [Member] Twenty Seventeen Grant 1 [Member] Twenty Seventeen Grant 1 [Member] 2017 Grant 2 [Member] Twenty Seventeen Grant 2 [Member] Twenty Seventeen Grant 2 [Member] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Scenario, Forecast [Member] Scenario, Forecast [Member] Schedule of Long term Incentive Compensation Arrangement by Award Plan Name [Axis] Schedule of Long term Incentive Compensation Arrangement by Award Plan Name [Axis] Pertinent data describing and reflecting required disclosures pertaining to an incentive compensation arrangement, by plan. Incentive Compensation Arrangements by Award Plan Name [Domain] Incentive Compensation Arrangements by Award Plan Name [Domain] Incentive compensation plans including multiple payment arrangements. Incentive Compensation Plan [Member] Alliance Bernstein Incentive Compensation Award Program [Member] Incentive compensation plan under which annual awards may be granted to eligible employees 2017 Long Term Incentive Plan [Member] Long Term Incentive Plan 2010 [Member] New long Term Incentive Plan adopted on June 30, 2010 and became effective on July 1, 2010. Long Term Incentive Plan [Member] Long Term Incentive Plan 1997 [Member] New long Term Incentive Plan adopted in 1997. Employment and Separation Agreements [Member] Employee Severance [Member] Employee Stock Option [Member] Employee Stock Option [Member] Stock Compensation Plan [Member] Stock Compensation Plan [Member] Director [Member] Director [Member] Board of Directors Chairman [Member] Board of Directors Chairman [Member] President and CEO [Member] President and CEO [Member] President and CEO [Member] CEO [Member] Chief Executive Officer [Member] Employee [Member] Employee [Member] Refers to employee of an entity. Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] 33.3% of Options and 25% of Restricted AB Holding Units, First Anniversary Vesting Period [Member] Share-based Compensation Award, Tranche One [Member] 33.3% of Options and 25% of Restricted AB Holding Units, Second Anniversary Vesting Period [Member] Share-based Compensation Award, Tranche Two [Member] 33.3% of Options and 25% of Restricted AB Holding Units, Third Anniversary Vesting Period [Member] Share-based Compensation Award, Tranche Three [Member] 25% of Restricted AB Holding Units, Fourth Anniversary Vesting Period [Member] Share-based Compensation Award, Tranche Four [Member] Share-based Compensation Award, Tranche Four [Member] Aggregate value awards under combined incentive plans Deferred Compensation Arrangement with Individual, Fair Value of Shares Issued Long-term incentive compensation charge Deferred Compensation Arrangement with Individual, Compensation Expense Compensation plan expire date Share-based Compensation Arrangement by Share-based Payment Award, Expiration Date Units to be granted after plan expiration Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Maximum number of awards authorized for issuance (in units) Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee Number of newly-issued units (in units) Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Granted AB holding unit net of forfeitures (in units) Share based Compensation Arrangement by Share based Payment Award, Units, Granted Net of forfeitures Number of holding units granted, net of forfeitures. AB Holding units available for future grant (in units) Common Stock, Capital Shares Reserved for Future Issuance Annual vesting percentage for the term of award Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Grant date fair value (in dollars per unit) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Total intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Compensation costs not yet recognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options Weighted average grant date fair value (in dollars per unit) Unrecognized compensation cost Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Grant date fair value of awards Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Grants In Period, Fair Value Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Grants In Period, Fair Value Service requirement Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Additional AB restricted units granted (in units) Additional Restricted Units Granted The number of additional grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Grant date fair value of vested shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Number of unvested restricted AB Holding Units Number of restricted AB Units without a service requirement Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested Without Service Requirement Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested Without Service Requirement Number of restricted AB Units with a service requirement Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested With Service Requirement Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested With Service Requirement Period of recognition (in years) Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Business Segment Information Segment Reporting Disclosure [Text Block] Revenues for Services Provided or Related to the Mutual Funds Revenues for Services Provided or Related to the Mutual Funds [Table Text Block] A tabular disclosure for revenues for services provided or related to the mutual funds which includes investment management, distribution, shareholder and administrative, and brokerage services. Consolidated Financial Statements for Transactions with Related Parties Schedule of Related Party Transactions [Table Text Block] Statement of Partners' Capital [Abstract] Partner Type [Axis] Partner Type [Axis] Partner Type of Partners' Capital Account, Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] General Partner's Capital [Member] General Partner [Member] Limited Partners' Capital [Member] Limited Partner [Member] Receivables from Affiliates [Member] Capital Contribution Receivable [Member] The receivables account for money due the Entity for capital Contributions. AB Holding Units Held for Long-tem Incentive Compensation Plans [Member] Deferred Compensation, Share-based Payments [Member] Accumulated Other Comprehensive Income (Loss) [Member] AOCI Attributable to Parent [Member] Non-redeemable Non-controlling Interests in Consolidated Entities [Member] Noncontrolling Interest [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance, beginning of year Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Cash distributions Partners' Capital Account, Distributions Long-term incentive compensation plans activity Partners' Capital Account, Deferred Compensation (Retirement) issuance of AB Units, net Stock Repurchased and Retired During Period, Value Other Stockholders' Equity, Other Capital contributions from General Partner Compensation plan accrual Partners Capital Deferred Compensation Plan Accrual Compensation plan accrual. Capital contributions from AB Holding Capital Contributions received from Related Parties The cash inflow related to capital contributions received from related parties. Purchases of AB Holding Units to fund long-term compensation plans, net Partners' Capital Account, Treasury Units, Purchased Long-term incentive compensation awards expense Partners' Capital Account, Deferred Compensation Amortization The amortization of each class of partners' capital accounts during the year due to deferred compensation amortization. Partners include general, limited and preferred partners. Re-valuation of AB Holding Units held in rabbi trust Re-valuation of Holding Units held in Rabbi Trust Amount of increase (decrease) to additional paid in capital (APIC) resulting from reconciliation of prices of activity (issuances, forfeitures, repurchases, retirements) in rabbi trust. Unrealized gain (loss) on investments, net of tax Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Foreign currency translation adjustment Purchase of non-controlling interest Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Changes in employee benefit related items, net of tax Net income Distributions (to) from non-controlling interests of our consolidated venture capital fund activities Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Balance, end of year Earnings Before Income Taxes and Income Tax Expense Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Difference Between the Effective Tax Rates and UBT Statutory Tax Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Tax Effect of Significant Items Comprising the Net Deferred Tax Asset (Liability) Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Deferred Sales Commissions, Net Deferred Sales Commissions Net [Text Block] Disclosure related to our deferred sales commissions showing the components of deferred sales commissions, net as well as the current and future amortization expense. Non-controlling Interests Noncontrolling Interest Disclosure [Text Block] Mutual Funds [Member] Mutual Fund [Member] Distribution revenues Shareholder servicing fees Distribution and Servicing Fees Business Combinations [Abstract] Ramius Alternative Solutions LLC [Member] Ramius Alternative Solutions LLC [Member] Ramius Alternative Solutions LLC [Member] CPH Capital Fondsmaeglerselskab A/S [Member] CPH Capital Fondsmaeglerselskab A/S [Member] CPH Capital Fondsmaeglerselskab A/S 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] Investment Management Contract [Member] Investment Management Contracts [Member] Investment Management Contracts Ownership percentage Business Acquisition, Percentage of Voting Interests Acquired Assets under management Assets under Management, Carrying Amount Cash paid Payments to Acquire Businesses, Gross Revenue remeasurement period Business Combination, Projected Fee Revenues, Remeasurement Period Business Combination, Projected Fee Revenues, Remeasurement Period Finite-lived intangible assets acquired Finite-lived Intangible Assets Acquired Assets under management remeasurement period Business Combination, Assets Under Management, Remeasurement Period Business Combination, Assets Under Management, Remeasurement Period Indefinite-lived intangible assets acquired Indefinite-lived Intangible Assets Acquired Redeemable non-controlling interest Income Statement [Abstract] Dividend and interest income Interest and Dividend Income, Operating Investment gains (losses) Principal Investment Gain (Loss) Expenses: Employee compensation and benefits Labor and Related Expense Promotion and servicing: Transfers and Servicing [Abstract] Distribution-related payments Trade execution, marketing, T&E and other General and administrative: General and Administrative Expense [Abstract] Contingent payment arrangements Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Interest on borrowings Interest Expense, Borrowings Amortization of intangible assets Operating income Operating Income (Loss) Income tax Net income Net income of consolidated entities attributable to non-controlling interests Net income attributable to AB Unitholders Net income per AB Unit: Earnings Per Unit [Abstract] Basic (in dollars per share) Diluted (in dollars per share) Schedule of Revenues from External Customers and Long-Lived Assets [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Statement, Geographical [Axis] Geographical [Axis] Segment, Geographical [Domain] Geographical [Domain] United States [Member] UNITED STATES International [Member] International [Member] Revenues from external customers attributed to all foreign countries in total from which the entity derives revenues Revenues from External Customers and Long-Lived Assets [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Geographic Information [Abstract] Segments, Geographical Areas [Abstract] Long-lived assets Long-Lived Assets Consolidated Company-Sponsored Investment Funds Variable Interest Entity Disclosure [Text Block] Real Estate Charges Restructuring and Related Activities Disclosure [Text Block] Summary of Investment Holdings [Table] Summary of Investment Holdings [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] US Treasury Bill Securities [Member] Long-term Incentive Compensation-Related [Member] Long-term Incentive Compensation-Related [Member] Investments are typically made in services that are notionally elected by long-term incentive compensation plan participants and maintained in a consolidated rabbi trust or separate custodial account. The rabbi trust and custodial account enable the company to hold such investments separate from our other assets for the purpose of settling our obligations to participants. Equities [Member] Investments In Limited Partnership Hedge Funds [Member] Investments In Limited Partnership Hedge Funds [Member] The underlying investments of the limited partnership hedge funds invested in include long and short positions in equity securities, fixed income securities (including various agency and non-agency asset-based securities), currencies, commodities and derivatives (including various swaps and forward contracts). These investments are valued at quoted market prices or, where quoted market prices are not available, are fair valued based on the pricing policies and procedures of the underlying funds. Private Equity [Member] Private Equity [Member] Investments held in private equity. Trading Securities [Member] Trading Securities [Member] Other Investment [Member] Other Investment [Member] Investment instruments not otherwise previously disclosed. Summary of Investment Holdings [Line Items] Summary of Investment Holdings [Line Items] Valuation and Qualifying Accounts Disclosure [Table] Valuation and Qualifying Accounts Disclosure [Table] AllianceBernstein L.P. [Member] AllianceBernstein L.P. [Member] AllianceBernstein L.P. [Member] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves [Domain] Valuation Allowances and Reserves [Domain] Allowance for Doubtful Accounts [Member] Allowance for Doubtful Accounts [Member] Valuation and Qualifying Accounts Disclosure [Line Items] Valuation and Qualifying Accounts Disclosure [Line Items] Movement in Valuation Allowances and Reserves Movement in Valuation Allowances and Reserves [Roll Forward] Balance at Beginning of Period Valuation Allowances and Reserves, Balance Credited to Costs and Expenses Valuation Allowances and Reserves, Additions for Charges to Cost and Expense Deductions Valuation Allowances and Reserves, Deductions Balance at End of Period Amounts written-off as uncollectible Allowance for Doubtful Accounts Receivable, Write-offs Futures, forwards and swaps held Derivative Asset, Fair Value, Amount Not Offset Against Collateral Gains (losses) on derivatives Cash collateral payable to trade counterparties Cash collateral received Net assets of investment products that are non-consolidated VIEs Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net Maximum risk of loss in investment in VIEs Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Reclassification (see below) Realized gains, net Ownership structure of AB Holding [Axis] Ownership structure of AB Holding [Axis] Ownership structure of AB Holding [Axis] Ownership structure of AB Holding [Domain] Ownership structure of AB Holding [Domain] [Domain] for Ownership structure of AB Holding [Axis] AXA And Its Subsidiaries [Member] Ownership structure of AB expressed as percentage of general and limited partnership interests Limited Liability Company or Limited Partnership, Business Organization and Operations [Abstract] General Partnership number of general partnership units owned in Holding Company (in units) General Partners' Capital Account, Units Outstanding AXA and its subsidiaries economic interest in Company Limited Liability Company Llc Or Limited Partnership Lp Members Or Limited Partners Economic Interest In Company Economic interest in AllianceBernstein owned by specific named entity as a General Partner and Limited Partner in Holding and AllianceBernstein, expressed as a percentage of total. Acquisitions Business Combination Disclosure [Text Block] Long-term Incentive Compensation Plans Compensation Related Costs, General [Text Block]