Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	AB CAP FUND, INC.
Prospectus Date	rr_ProspectusDate	Nov. 29, 2019
AB Multi-Manager Select 2010 Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	AB Multi-Manager Select 2010 Fund
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund’s investment objective is to seek the highest total return (total return includes capital appreciation and income) over time consistent with its asset mix.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in AB Mutual Funds. More information about these and other discounts is available from your financial intermediary and in Investing in the Funds—Sales Charge Reduction Programs for Class A Shares on page 79 of this Prospectus, in Appendix B—Financial Intermediary Waivers of this Prospectus and in Purchase of Shares—Sales Charge Reduction Programs for Class A Shares on page 113 of the Fund’s Statement of Additional Information (“SAI”). You may be required to pay commissions and/or other forms of compensation to a broker for transactions in Advisor Class shares, which are not reflected in the tables or the examples below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	November 30, 2020
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund (or an Underlying Fund) pays transaction costs, such as commissions, when it buys or sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These transaction costs, which are not reflected in the Annual Fund Operating Expenses or in the Examples, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate (which does not reflect purchases and sales of securities by the Underlying Funds) was 46% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	46.00%
Expenses Deferred Charges [Text Block]	rr_ExpensesDeferredChargesTextBlock	As described below under “Purchase and Sale of Fund Shares”, initial sales charges and contingent deferred sales charges (“CDSC”) are being waived in light of the pending liquidation of the Fund. Absent the waiver of these charges, the maximum initial sales charge imposed on purchases of Class A shares would be 4.25%; certain purchases of Class A shares in amounts of $1,000,000 or more, or by certain group retirement plans, would be subject to a 1%, 1-year CDSC; and purchases of Class C shares would be subject to a 1%, 1-year CDSC. Class C shares automatically convert to Class A shares after ten years.
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in AB Mutual Funds.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 100,000
Expense Example [Heading]	rr_ExpenseExampleHeading	Examples
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The Examples are intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Examples assume that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Examples also assume that your investment has a 5% return each year, that the Fund’s operating expenses stay the same and that any fee waiver is in effect only for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks the highest total return over time consistent with its asset mix. Total return includes capital growth and income. To achieve its investment objective, the Fund focuses its investments while minimizing short term risks on a combination of AB Mutual Funds and mutual funds and exchange-traded funds, or ETFs, managed by unaffiliated third parties (“Underlying Funds”) representing a variety of asset classes and investment styles. The Fund invests in the Underlying Funds in accordance with its target asset mix. In order to implement the Fund’s investment strategies, Morningstar Investment Management LLC (“Morningstar”), the Fund’s sub-adviser, selects Underlying Funds within each asset class for investment by the Fund from among AB Mutual Funds and funds offered by other fund complexes that have entered into a participation agreement or similar arrangement with the Fund. The Adviser has directed Morningstar to normally select Underlying Funds so that 10% to 50% of the Fund’s net assets is invested in AB Mutual Funds. ETFs will normally represent a significant portion of the Fund’s investments, and these ETFs are typically passive vehicles intended to track the performance of particular securities indices rather than actively-managed funds. The Fund is managed to the specific year of planned retirement included in its name (the “retirement date”), in this case, 2010. The Fund’s asset mix will become more conservative, with an increasing exposure to investments in fixed-income securities and short-term bonds, each year until reaching the year approximately fifteen years after the retirement date. At that time, the Fund will no longer be managed to become more conservative each year, although the Adviser may continue to vary the relative weightings of the Fund’s asset classes as described below. This strategy reflects the objective of pursuing the maximum amount of total return, consistent with a reasonable amount of risk, during the investor’s pre-retirement and early retirement years. After the retirement date of the Fund, the Fund’s investment mix anticipates that an investor may take withdrawals from his or her account to provide supplemental retirement income and seeks to minimize the likelihood that an investor in the Fund experiences a significant loss of capital at a more advanced age. The Fund allocates its investments in Underlying Funds that invest in the following asset classes: traditional equity securities, defensive equity securities, equity diversifiers, inflation sensitive instruments, fixed-income diversifiers, core fixed-income securities and short duration fixed-income securities (including high yield bonds or “junk bonds”). For these purposes, inflation sensitive instruments include investments in funds focused on real estate securities, commodities and inflation-indexed securities, fixed-income diversifiers include investments in funds engaged in certain alternative strategies that seek reduced volatility and low correlation with fixed-income markets such as market neutral funds, short duration fixed-income securities include investments in funds focused on minimizing risk of loss by maintaining average maturities of three years or less, defensive equity securities include investments in funds focusing on low volatility equities and other equity strategies emphasizing high-quality cash flows and dividends, and equity diversifiers include investments in funds engaged in certain alternative strategies that seek reduced volatility and limited correlation with equity markets such as equity long/short funds. The Fund may also invest directly in investments in each asset class. Each Underlying Fund may enter into derivatives transactions, such as options, futures contracts, forwards and swaps, in an effort to earn income, to gain or adjust exposure to individual securities or markets, or to protect all or a portion of the Underlying Fund’s portfolio from a decline in value. The Fund’s current target asset mix (based on the Fund’s distance from its retirement date) is approximately 27.8% core fixed-income securities, 21.2% traditional equity securities, 18.4% inflation sensitive instruments, 14.0% short duration fixed-income securities, 11.8% defensive equity securities, 4.9% fixed-income diversifiers and 2.0% equity diversifiers. The Fund’s investments in fixed-income and equity asset classes may include Underlying Funds investing in U.S. and non-U.S. securities. The Adviser will cause the relative weightings of the Fund’s asset classes to vary from the target asset mix in light of market conditions and forecasts, but usually by not more than plus/minus 10%. Appreciation and/or depreciation of the Underlying Funds representing various asset classes may cause the relative weightings to vary by more than 10%, and during adverse market conditions the Adviser may cause the relative weightings to be more than 10% more conservative than the typical asset mix for that point in time. In making asset allocation decisions, the Adviser uses its proprietary dynamic asset allocation process (“DAA”). DAA comprises a series of analytical and forecasting tools employed by the Adviser to gauge fluctuations in the risk/return profile of various asset classes. DAA will aim to adjust the Fund’s investment exposure in changing market conditions and thereby reduce overall portfolio volatility by mitigating the effects of market fluctuations, while preserving consistent long-term return potential. For example, the Adviser may seek to reduce the Fund’s risk exposure to one or more asset classes when DAA suggests that market risks relevant to those asset classes are rising but return opportunities are declining. The Adviser expects to pursue this process for the Fund primarily by adjusting Underlying Fund investments. The following chart illustrates how the asset mix of the Fund will vary over time. In general, the asset mix of the Fund will gradually shift from one comprised largely of Underlying Funds that emphasize investments in equity securities to one that is comprised of a mixture of Underlying Funds that invest in fixed-income securities (including short-duration bonds) and equity securities.
Risk [Heading]	rr_RiskHeading	PRINCIPAL RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The value of your investment in the Fund will change with changes in the values of the Fund’s investments in the Underlying Funds. There is no assurance that the Fund will provide an investor with adequate income at or through retirement. Market Risk: The value of the Fund’s investments will fluctuate as the stock or bond market fluctuates. The value of its investments may decline, sometimes rapidly and unpredictably, simply because of economic changes or other events that affect large portions of the market. It includes the risk that a particular style of investing may be underperforming the stock market generally. Allocation Risk: The allocation of investments among the Underlying Funds’ different investment styles, such as equity or debt securities, or U.S. or non-U.S. securities, may have a more significant effect on the Fund’s net asset value (“NAV”) when one of these investments is performing more poorly than the other. There is no assurance that allocation decisions will result in the desired effects. Subjective decisions made by the Adviser and/or Morningstar may cause the Fund to incur losses or to miss profit opportunities on which it might otherwise have capitalized. The limited universe of Underlying Funds and the requirement that a specified percentage of Fund assets be invested in AB Mutual Funds as noted above may adversely affect Fund performance. Interest Rate Risk: Changes in interest rates will affect the value of the Fund’s investments in Underlying Funds that invest in fixed-income securities. When interest rates rise, the value of existing investments in fixed-income securities tends to fall and this decrease in value may not be offset by higher income from new investments. Interest rate risk is generally greater for fixed-income securities with longer maturities or durations. Credit Risk: An issuer or guarantor of a fixed-income security, or the counterparty to a derivatives or other contract, may be unable or unwilling to make timely payments of interest or principal, or to otherwise honor its obligations. The issuer or guarantor may default, causing a loss of the full principal amount of a security and accrued interest. The degree of risk for a particular security may be reflected in its credit rating. There is the possibility that the credit rating of a fixed-income security may be downgraded after purchase, which may adversely affect the value of the security. Investments by Underlying Funds in fixed-income securities with lower ratings are subject to a higher probability that an issuer will default or fail to meet its payment obligations. High Yield Debt Security Risk: Investments in fixed-income securities with ratings below investment grade, commonly known as “junk bonds”, tend to have a higher probability that an issuer will default or fail to meet its payment obligations. These securities may be subject to greater price volatility due to such factors as specific corporate developments, interest rate sensitivity and negative perceptions of the junk bond market generally, and may be more difficult to trade than other types of securities. Inflation Risk: This is the risk that the value of assets or income from the Fund’s investments in the Underlying Funds will be less in the future as inflation decreases the value of money. As inflation increases, the value of each Underlying Fund’s assets can decline as can the value of that Underlying Fund’s distributions. Foreign (Non-U.S.) Risk: Investments in non-U.S. issuers by Underlying Funds may involve more risk than investments in U.S. issuers. These securities may fluctuate more widely in price and may be more difficult to trade due to adverse market, economic, political, regulatory or other factors. Currency Risk: Fluctuations in currency exchange rates may negatively affect the value of the Fund’s investments or reduce its returns. Capitalization Risk: Investments in small- and mid-capitalization companies by Underlying Funds tend to be more volatile than investments in large-capitalization companies. Investments in small-capitalization companies may have additional risks because these companies often have limited product lines, markets, or financial resources. Derivatives Risk: Derivatives may be difficult to price or unwind and leveraged so that small changes may produce disproportionate losses for the Fund. Derivatives, especially over-the-counter derivatives, are also subject to counterparty risk. Leverage Risk: Borrowing money or other leverage may make an Underlying Fund’s investments more volatile because leverage tends to exaggerate the effect of any increase or decrease in the value of its investments. An Underlying Fund may create leverage through the use of certain portfolio management techniques such as reverse repurchase agreements or forward commitments, or by borrowing money. Investment in Other Investment Companies Risk: As with other investments, investments in other investment companies, including ETFs, are subject to market and selection risk. In addition, shareholders of the Fund bear both their proportionate share of expenses in the Fund (including management fees) and, indirectly, the expenses of the investment companies. Management Risk: The Fund is subject to management risk because it is an actively-managed investment fund. The Adviser and Morningstar will apply their investment techniques and risk analyses in making investment decisions for the Fund, but there is no guarantee that their techniques will produce the intended results. As with all investments, you may lose money by investing in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, you may lose money by investing in the Fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	BAR CHART AND PERFORMANCE INFORMATION
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and performance information provide an indication of the historical risk of an investment in the Fund by showing: how the Fund's performance changed from year to year over the life of the Fund; and how the Fund's average annual returns for one year and since inception compare to those of a broad-based securities market index. You may obtain updated performance information on the Fund’s website at www.abfunds.com (click on “Investments—Mutual Funds”). The Fund's past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	how the Fund’s performance changed from year to year over the life of the Fund; and how the Fund’s average annual returns for one year and since inception compare to those of a broad-based securities market index.
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.abfunds.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Bar Chart
Bar Chart Narrative [Text Block]	rr_BarChartNarrativeTextBlock	The annual returns in the bar chart are for the Fund’s Class A shares and do not reflect sales loads. If sales loads were reflected, returns would be less than those shown. Through September 30, 2019, the year-to-date unannualized return for Class A shares was 9.54%.
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	The annual returns in the bar chart are for the Fund’s Class A shares and do not reflect sales loads. If sales loads were reflected, returns would be less than those shown.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Calendar Year End (%) During the period shown in the bar chart, the Fund’s: Best Quarter was up 3.07%, 1st quarter, 2017; and Worst Quarter was down -4.82%, 4th quarter, 2018.
Performance Table Heading	rr_PerformanceTableHeading	Performance Table Average Annual Total Returns (For the periods ended December 31, 2018)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns: – Are an estimate, which is based on the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes;
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	actual after-tax returns depend on an individual investor’s tax situation and are likely to differ from those shown; and – Are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns: – Are shown for Class A shares only and will vary for the other Classes of shares because these Classes have different expense ratios;
AB Multi-Manager Select 2010 Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none	[1]
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none	[1]
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.15%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.69%
Other Expenses	rr_Component2OtherExpensesOverAssets	1.55%
Total Other Expenses	rr_OtherExpensesOverAssets	2.24%
Acquired Fund Fees and Expenses (Underlying Funds)	rr_AcquiredFundFeesAndExpensesOverAssets	0.52%	[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	3.16%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(2.21%)	[3]
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	rr_NetExpensesOverAssets	0.95%
After 1 Year	rr_ExpenseExampleYear01	$ 518
After 3 Years	rr_ExpenseExampleYear03	1,159
After 5 Years	rr_ExpenseExampleYear05	1,824
After 10 Years	rr_ExpenseExampleYear10	$ 3,597
2009	rr_AnnualReturn2009
2010	rr_AnnualReturn2010
2011	rr_AnnualReturn2011
2012	rr_AnnualReturn2012
2013	rr_AnnualReturn2013
2014	rr_AnnualReturn2014
2015	rr_AnnualReturn2015	(1.71%)
2016	rr_AnnualReturn2016	6.12%
2017	rr_AnnualReturn2017	11.11%
2018	rr_AnnualReturn2018	(4.31%)
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2019
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	9.54%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	3.07%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2018
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(4.82%)
1 Year	rr_AverageAnnualReturnYear01	(8.40%)	[4]
Since Inception	rr_AverageAnnualReturnSinceInception	1.87%	[4],[5]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2014	[4]
AB Multi-Manager Select 2010 Fund | Class C
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none	[1]
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.15%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%	[6]
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.70%
Other Expenses	rr_Component2OtherExpensesOverAssets	1.52%
Total Other Expenses	rr_OtherExpensesOverAssets	2.22%
Acquired Fund Fees and Expenses (Underlying Funds)	rr_AcquiredFundFeesAndExpensesOverAssets	0.52%	[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	3.14%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(2.19%)	[3]
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	rr_NetExpensesOverAssets	0.95%
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	Restated to reflect current fees in connection with the pending liquidation of the Fund (as described below under “Purchase and Sale of Fund Shares”).
After 1 Year	rr_ExpenseExampleYear01	$ 97
After 3 Years	rr_ExpenseExampleYear03	763
After 5 Years	rr_ExpenseExampleYear05	1,453
After 10 Years	rr_ExpenseExampleYear10	$ 3,295
1 Year	rr_AverageAnnualReturnYear01	(5.85%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.18%	[5]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2014
AB Multi-Manager Select 2010 Fund | Advisor Class
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.15%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.67%
Other Expenses	rr_Component2OtherExpensesOverAssets	1.54%
Total Other Expenses	rr_OtherExpensesOverAssets	2.21%
Acquired Fund Fees and Expenses (Underlying Funds)	rr_AcquiredFundFeesAndExpensesOverAssets	0.52%	[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.88%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(2.18%)	[3]
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	rr_NetExpensesOverAssets	0.70%
After 1 Year	rr_ExpenseExampleYear01	$ 72
After 3 Years	rr_ExpenseExampleYear03	685
After 5 Years	rr_ExpenseExampleYear05	1,325
After 10 Years	rr_ExpenseExampleYear10	$ 3,047
1 Year	rr_AverageAnnualReturnYear01	(3.94%)
Since Inception	rr_AverageAnnualReturnSinceInception	3.24%	[5]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2014
AB Multi-Manager Select 2010 Fund | Class R
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.15%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%	[6]
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.26%
Other Expenses	rr_Component2OtherExpensesOverAssets	1.54%
Total Other Expenses	rr_OtherExpensesOverAssets	1.80%
Acquired Fund Fees and Expenses (Underlying Funds)	rr_AcquiredFundFeesAndExpensesOverAssets	0.52%	[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.72%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.77%)	[3]
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	rr_NetExpensesOverAssets	0.95%
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	Restated to reflect current fees in connection with the pending liquidation of the Fund (as described below under “Purchase and Sale of Fund Shares”).
After 1 Year	rr_ExpenseExampleYear01	$ 97
After 3 Years	rr_ExpenseExampleYear03	676
After 5 Years	rr_ExpenseExampleYear05	1,282
After 10 Years	rr_ExpenseExampleYear10	$ 2,921
1 Year	rr_AverageAnnualReturnYear01	(4.54%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.70%	[5]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2014
AB Multi-Manager Select 2010 Fund | Class K
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.15%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.19%
Other Expenses	rr_Component2OtherExpensesOverAssets	1.54%
Total Other Expenses	rr_OtherExpensesOverAssets	1.73%
Acquired Fund Fees and Expenses (Underlying Funds)	rr_AcquiredFundFeesAndExpensesOverAssets	0.52%	[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.65%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.70%)	[3]
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	rr_NetExpensesOverAssets	0.95%
After 1 Year	rr_ExpenseExampleYear01	$ 97
After 3 Years	rr_ExpenseExampleYear03	661
After 5 Years	rr_ExpenseExampleYear05	1,253
After 10 Years	rr_ExpenseExampleYear10	$ 2,857
1 Year	rr_AverageAnnualReturnYear01	(4.32%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.93%	[5]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2014
AB Multi-Manager Select 2010 Fund | Class I
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.15%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.07%
Other Expenses	rr_Component2OtherExpensesOverAssets	1.53%
Total Other Expenses	rr_OtherExpensesOverAssets	1.60%
Acquired Fund Fees and Expenses (Underlying Funds)	rr_AcquiredFundFeesAndExpensesOverAssets	0.52%	[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.27%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.57%)	[3]
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	rr_NetExpensesOverAssets	0.70%
After 1 Year	rr_ExpenseExampleYear01	$ 72
After 3 Years	rr_ExpenseExampleYear03	558
After 5 Years	rr_ExpenseExampleYear05	1,072
After 10 Years	rr_ExpenseExampleYear10	$ 2,483
1 Year	rr_AverageAnnualReturnYear01	(4.05%)
Since Inception	rr_AverageAnnualReturnSinceInception	3.19%	[5]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2014
AB Multi-Manager Select 2010 Fund | Class Z
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.15%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses: Transfer Agent	rr_Component1OtherExpensesOverAssets	0.02%
Other Expenses	rr_Component2OtherExpensesOverAssets	1.53%
Total Other Expenses	rr_OtherExpensesOverAssets	1.55%
Acquired Fund Fees and Expenses (Underlying Funds)	rr_AcquiredFundFeesAndExpensesOverAssets	0.52%	[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.22%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(1.52%)	[3]
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	rr_NetExpensesOverAssets	0.70%
After 1 Year	rr_ExpenseExampleYear01	$ 72
After 3 Years	rr_ExpenseExampleYear03	548
After 5 Years	rr_ExpenseExampleYear05	1,050
After 10 Years	rr_ExpenseExampleYear10	$ 2,435
1 Year	rr_AverageAnnualReturnYear01	(4.06%)
Since Inception	rr_AverageAnnualReturnSinceInception	3.21%	[5]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2014
AB Multi-Manager Select 2010 Fund | Return After Taxes on Distributions | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(9.71%)	[4]
Since Inception	rr_AverageAnnualReturnSinceInception	1.10%	[4],[5]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2014	[4]
AB Multi-Manager Select 2010 Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(4.44%)	[4]
Since Inception	rr_AverageAnnualReturnSinceInception	1.26%	[4],[5]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2014	[4]
AB Multi-Manager Select 2010 Fund | S&P Target Date 2010 Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(3.10%)
Since Inception	rr_AverageAnnualReturnSinceInception	3.33%	[5]

[1] As described below under “Purchase and Sale of Fund Shares”, initial sales charges and contingent deferred sales charges (“CDSC”) are being waived in light of the pending liquidation of the Fund. Absent the waiver of these charges, the maximum initial sales charge imposed on purchases of Class A shares would be 4.25%; certain purchases of Class A shares in amounts of $1,000,000 or more, or by certain group retirement plans, would be subject to a 1%, 1-year CDSC; and purchases of Class C shares would be subject to a 1%, 1-year CDSC. Class C shares automatically convert to Class A shares after ten years.

[2] Acquired Fund Fees and Expenses include interest expense and certain costs related to short sales of the Underlying Funds. Without such expenses included, Acquired Fund Fees and Expenses would be .40%, and Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement would be .83%, .83%, .58%, .83%, .83%, .58% and .58% of average daily net assets, respectively, for Class A, Class C, Advisor Class, Class R, Class K, Class I and Class Z shares.

[3] The Adviser has contractually agreed to waive its management fees and/or to bear expenses of the Fund until November 30, 2020 to the extent necessary to prevent total Fund operating expenses (excluding acquired fund fees and expenses, interest expense, taxes, extraordinary expenses, and brokerage commissions and other transaction costs), on an annualized basis, from exceeding .43%, .43%, .18%, .43%, .43%, .18% and .18% of average daily net assets, respectively, for Class A, Class C, Advisor Class, Class R, Class K, Class I and Class Z shares (“expense limitations”). The expense limitations will remain in effect until November 30, 2020 and will continue thereafter from year to year unless the Adviser provides notice of termination to the Fund at least 60 days prior to the end of the period. Any fees waived and expenses borne by the Adviser through January 5, 2016 under the expense limitation in effect prior to that date may be reimbursed by the Fund until the end of the third fiscal year after the fiscal period in which the fee was waived or the expense was borne, provided that no reimbursement payment will be made that would cause the Fund’s operating expenses to exceed the applicable expense limitations. In connection with the Fund’s investments in AB Government Money Market Portfolio (the “Money Market Portfolio”) (except for the investment of any cash collateral from securities lending), the Adviser has contractually agreed to waive its management fee from the Fund and/or reimburse other expenses of the Fund in an amount equal to the Fund’s pro rata share of the Money Market Portfolio’s effective management fee, as included in “Acquired Fund Fees and Expenses”.

[4] After-tax returns: – Are shown for Class A shares only and will vary for the other Classes of shares because these Classes have different expense ratios; – Are an estimate, which is based on the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes; actual after-tax returns depend on an individual investor’s tax situation and are likely to differ from those shown; and – Are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

[5] Inception date: 12/15/2014.

[6] Restated to reflect current fees in connection with the pending liquidation of the Fund (as described below under “Purchase and Sale of Fund Shares”). The Fund’s Board of Directors has limited the Fund’s distribution and/or service (Rule 12b-1) fees to an annual rate not in excess of .25%. Absent this limitation, Class C shares and Class R shares would be subject to 12b-1 fees of 1.00% and .50%, respectively.