Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK GLOBAL ALLOCATION FUND, INC.
Prospectus Date	rr_ProspectusDate	Jun. 08, 2016
BLACKROCK GLOBAL ALLOCATION FUND, INC.
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Global Allocation Fund, Inc.
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of the BlackRock Global Allocation Fund, Inc. (the “Fund”) is to provide high total investment return through a fully managed investment policy utilizing United States and foreign equity securities, debt and money market securities, the combination of which will be varied from time to time both with respect to types of securities and markets in response to changing market and economic trends. Total return means the combination of capital growth and investment income.
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 Class K Shares of the Fund.
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)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 84% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	84.00%
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	Other Expenses are based on estimated amounts for the current fiscal year.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes 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 Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund invests in a portfolio of equity, debt and money market securities. Generally, the Fund’s portfolio will include both equity and debt securities. Equity securities include common stock, preferred stock, securities convertible into common stock, rights and warrants or securities or other instruments whose price is linked to the value of common stock. At any given time, however, the Fund may emphasize either debt securities or equity securities. In selecting equity investments, the Fund mainly seeks securities that Fund management believes are undervalued. The Fund may buy debt securities of varying maturities, debt securities paying a fixed or fluctuating rate of interest, and debt securities of any kind, including, by way of example, securities issued or guaranteed by the U.S. Government or its agencies or instrumentalities, by foreign governments or international agencies or supranational entities, or by domestic or foreign private issuers, debt securities convertible into equity securities, inflation-indexed bonds, structured notes, credit-linked notes, loan assignments and loan participations. In addition, the Fund may invest up to 35% of its total assets in “junk bonds,” corporate loans and distressed securities. The Fund may also invest in Real Estate Investment Trusts (“REITs”) and securities related to real assets (like real estate- or precious metals-related securities) such as stock, bonds or convertible bonds issued by REITs or companies that mine precious metals. When choosing investments, Fund management considers various factors, including opportunities for equity or debt investments to increase in value, expected dividends and interest rates. The Fund generally seeks diversification across markets, industries and issuers as one of its strategies to reduce volatility. The Fund has no geographic limits on where it may invest. This flexibility allows Fund management to look for investments in markets around the world, including emerging markets, that it believes will provide the best asset allocation to meet the Fund’s objective. The Fund may invest in the securities of companies of any market capitalization. Generally, the Fund may invest in the securities of corporate and governmental issuers located anywhere in the world. The Fund may emphasize foreign securities when Fund management expects these investments to outperform U.S. securities. When choosing investment markets, Fund management considers various factors, including economic and political conditions, potential for economic growth and possible changes in currency exchange rates. In addition to investing in foreign securities, the Fund actively manages its exposure to foreign currencies through the use of forward currency contracts and other currency derivatives. The Fund may own foreign cash equivalents or foreign bank deposits as part of the Fund’s investment strategy. The Fund will also invest in non-U.S. currencies. The Fund may underweight or overweight a currency based on the Fund management team’s outlook. The Fund’s composite Reference Benchmark has at all times since the Fund’s formation included a 40% weighting in non-US securities. The Reference Benchmark is an unmanaged weighted index comprised as follows: 36% of the S&P 500 Index; 24% FTSE World (ex US) Index; 24% BofA Merrill Lynch Current 5-year US Treasury Index; and 16% Citigroup Non-US Dollar World Government Bond Index. Throughout its history, the Fund has maintained a weighting in non-US securities, often exceeding the 40% Reference Benchmark weighting and rarely falling below this allocation. Under normal circumstances, the Fund will continue to allocate a substantial amount (approximately 40% or more — unless market conditions are not deemed favorable by BlackRock, in which case the Fund would invest at least 30%) — of its total assets in securities of (i) foreign government issuers, (ii) issuers organized or located outside the U.S., (iii) issuers which primarily trade in a market located outside the U.S., or (iv) issuers doing a substantial amount of business outside the U.S., which the Fund considers to be companies that derive at least 50% of their revenue or profits from business outside the U.S. or have at least 50% of their sales or assets outside the U.S. The Fund will allocate its assets among various regions and countries including the United States (but in no less than three different countries). For temporary defensive purposes the Fund may deviate very substantially from the allocation described above. The Fund may use derivatives, including options, futures, indexed securities, inverse securities, swaps and forward contracts both to seek to increase the return of the Fund and to hedge (or protect) the value of its assets against adverse movements in currency exchange rates, interest rates and movements in the securities markets. The Fund may seek to provide exposure to the investment returns of real assets that trade in the commodity markets through investment in commodity-linked derivative instruments and investment vehicles such as exchange traded funds that invest exclusively in commodities and are designed to provide this exposure without direct investment in physical commodities. The Fund may also gain exposure to commodity markets by investing up to 25% of its total assets in BlackRock Cayman Global Allocation Fund I, Ltd. (the “Subsidiary”), a wholly owned subsidiary of the Fund formed in the Cayman Islands, which invests primarily in commodity-related instruments. The Subsidiary may also hold cash and invest in other instruments, including fixed income securities, either as investments or to serve as margin or collateral for the Subsidiary’s derivative positions. The Subsidiary (unlike the Fund) may invest without limitation in commodity-related instruments.
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. The following is a summary description of principal risks of investing in the Fund. Commodities Related Investments Risks — Exposure to the commodities markets may subject the Fund to greater volatility than investments in traditional securities. The value of commodity-linked derivative investments may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity, such as drought, floods, weather, embargoes, tariffs and international economic, political and regulatory developments. Convertible Securities Risk — The market value of a convertible security performs like that of a regular debt security; that is, if market interest rates rise, the value of a convertible security usually falls. In addition, convertible securities are subject to the risk that the issuer will not be able to pay interest or dividends when due, and their market value may change based on changes in the issuer’s credit rating or the market’s perception of the issuer’s creditworthiness. Since it derives a portion of its value from the common stock into which it may be converted, a convertible security is also subject to the same types of market and issuer risks that apply to the underlying common stock. Corporate Loans Risk — Commercial banks and other financial institutions or institutional investors make corporate loans to companies that need capital to grow or restructure. Borrowers generally pay interest on corporate loans at rates that change in response to changes in market interest rates such as the London Interbank Offered Rate (“LIBOR”) or the prime rates of U.S. banks. As a result, the value of corporate loan investments is generally less exposed to the adverse effects of shifts in market interest rates than investments that pay a fixed rate of interest. The market for corporate loans may be subject to irregular trading activity and wide bid/ask spreads. In addition, transactions in corporate loans may settle on a delayed basis. As a result, the proceeds from the sale of corporate loans may not be readily available to make additional investments or to meet the Fund’s redemption obligations. To the extent the extended settlement process gives rise to short-term liquidity needs, the Fund may hold additional cash, sell investments or temporarily borrow from banks and other lenders. Debt Securities Risk — Debt securities, such as bonds, involve interest rate risk, credit risk, extension risk, and prepayment risk, among other things. Interest Rate Risk — The market value of bonds and other fixed-income securities changes in response to interest rate changes and other factors. Interest rate risk is the risk that prices of bonds and other fixed-income securities will increase as interest rates fall and decrease as interest rates rise. The Fund may be subject to a greater risk of rising interest rates due to the current period of historically low rates. For example, if interest rates increase by 1%, assuming a current portfolio duration of ten years, and all other factors being equal, the value of the Fund’s investments would be expected to decrease by 10%. The magnitude of these fluctuations in the market price of bonds and other fixed-income securities is generally greater for those securities with longer maturities. Fluctuations in the market price of the Fund’s investments will not affect interest income derived from instruments already owned by the Fund, but will be reflected in the Fund’s net asset value. The Fund may lose money if short-term or long-term interest rates rise sharply in a manner not anticipated by Fund management. To the extent the Fund invests in debt securities that may be prepaid at the option of the obligor (such as mortgage-backed securities), the sensitivity of such securities to changes in interest rates may increase (to the detriment of the Fund) when interest rates rise. Moreover, because rates on certain floating rate debt securities typically reset only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate debt securities. These basic principles of bond prices also apply to U.S. Government securities. A security backed by the “full faith and credit” of the U.S. Government is guaranteed only as to its stated interest rate and face value at maturity, not its current market price. Just like other fixed-income securities, government-guaranteed securities will fluctuate in value when interest rates change. A general rise in interest rates has the potential to cause investors to move out of fixed-income securities on a large scale, which may increase redemptions from funds that hold large amounts of fixed-income securities. Heavy redemptions could cause the Fund to sell assets at inopportune times or at a loss or depressed value and could hurt the Fund’s performance. Credit Risk — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on the issuer’s financial condition and on the terms of the securities. Extension Risk — When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these obligations to fall. Prepayment Risk — When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields. Derivatives Risk — The Fund’s use of derivatives may increase its costs, reduce the Fund’s returns and/or increase volatility. Derivatives involve significant risks, including: Volatility Risk — Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate with the overall securities markets. Counterparty Risk — Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Market and Liquidity Risk — The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. Valuation Risk — Valuation may be more difficult in times of market turmoil since many investors and market makers may be reluctant to purchase complex instruments or quote prices for them. Leverage Risk — Certain transactions in derivatives involve substantial leverage risk and may expose the Fund to potential losses that exceed the amount originally invested by the Fund. Tax Risk — Certain aspects of the tax treatment of derivative instruments, including swap agreements and commodity-linked derivative instruments, are currently unclear and may be affected by changes in legislation, regulations or other legally binding authority. Such treatment may be less favorable than that given to a direct investment in an underlying asset and may adversely affect the timing, character and amount of income the Fund realizes from its investments. Regulatory Risk — Derivative contracts, including, without limitation, swaps, currency forwards and non-deliverable forwards, are subject to regulation under the Dodd-Frank Wall Street Reform and Consumer Protection Act (“Dodd-Frank Act”) in the United States and under comparable regimes in Europe, Asia and other non-U.S. jurisdictions. Under the Dodd-Frank Act, certain derivatives may become subject to margin requirements when regulations are finalized. Implementation of such regulations under the Dodd-Frank Act regarding clearing, mandatory trading and margining of swaps and other derivatives may increase the costs to the Fund of trading in these instruments and, as a result, may affect returns to investors in the Fund. In December 2015, the Securities and Exchange Commission (the “SEC”) proposed a new rule to regulate the use of derivatives by registered investment companies, such as the Fund. If the rule goes into effect, it could limit the ability of the Fund to invest or remain invested in derivatives. Distressed Securities Risk — Distressed securities are speculative and involve substantial risks in addition to the risks of investing in junk bonds. The Fund will generally not receive interest payments on the distressed securities and may incur costs to protect its investment. In addition, distressed securities involve the substantial risk that principal will not be repaid. These securities may present a substantial risk of default or may be in default at the time of investment. The Fund may incur additional expenses to the extent it is required to seek recovery upon a default in the payment of principal of or interest on its portfolio holdings. In any reorganization or liquidation proceeding relating to a portfolio company, the Fund may lose its entire investment or may be required to accept cash or securities with a value less than its original investment. Distressed securities and any securities received in an exchange for such securities may be subject to restrictions on resale. Emerging Markets Risk — Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyperinflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets. Equity Securities Risk — Stock markets are volatile. The price of equity securities fluctuates based on changes in a company’s financial condition and overall market and economic conditions. Foreign Securities Risk — Foreign investments often involve special risks not present in U.S. investments that can increase the chances that the Fund will lose money. These risks include: The Fund generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight. Changes in foreign currency exchange rates can affect the value of the Fund’s portfolio. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments. The European financial markets have recently experienced volatility and adverse trends due to concerns about economic downturns in, or rising government debt levels of, several European countries. These events may spread to other countries in Europe. These events may affect the value and liquidity of certain of the Fund’s investments. Junk Bonds Risk — Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for the Fund. Leverage Risk — Some transactions may give rise to a form of economic leverage. These transactions may include, among others, derivatives, and may expose the Fund to greater risk and increase its costs. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet any required asset segregation requirements. Increases and decreases in the value of the Fund’s portfolio will be magnified when the Fund uses leverage. Market Risk and Selection Risk — Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by Fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money. Mid Cap Securities Risk — The securities of mid cap companies generally trade in lower volumes and are generally subject to greater and less predictable price changes than the securities of larger capitalization companies. Mortgage- and Asset-Backed Securities Risks — Mortgage- and asset-backed securities represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset-backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities. Precious Metal Related Securities Risk — Prices of precious metals and of precious metal related securities historically have been very volatile. The high volatility of precious metal prices may adversely affect the financial condition of companies involved with precious metals. The production and sale of precious metals by governments or central banks or other larger holders can be affected by various economic, financial, social and political factors, which may be unpredictable and may have a significant impact on the prices of precious metals. Other factors that may affect the prices of precious metals and securities related to them include changes in inflation, the outlook for inflation and changes in industrial and commercial demand for precious metals. Real Estate Related Securities Risk — The main risk of real estate related securities is that the value of the underlying real estate may go down. Many factors may affect real estate values. These factors include both the general and local economies, the amount of new construction in a particular area, the laws and regulations (including zoning, and tax laws) affecting real estate and the costs of owning, maintaining and improving real estate. The availability of mortgages and changes in interest rates may also affect real estate values. If the Fund’s real estate related investments are concentrated in one geographic area or in one property type, the Fund will be particularly subject to the risks associated with that area or property type. REIT Investment Risk — Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities. Small Cap and Emerging Growth Securities Risk — Small cap or emerging growth companies may have limited product lines or markets. They may be less financially secure than larger, more established companies. They may depend on a more limited management group than larger capitalized companies. Sovereign Debt Risk — Sovereign debt instruments are subject to the risk that a governmental entity may delay or refuse to pay interest or repay principal on its sovereign debt, due, for example, to cash flow problems, insufficient foreign currency reserves, political considerations, the relative size of the governmental entity’s debt position in relation to the economy or the failure to put in place economic reforms required by the International Monetary Fund or other multilateral agencies. Structured Notes Risk — Structured notes and other related instruments purchased by the Fund are generally privately negotiated debt obligations where the principal and/or interest is determined by reference to the performance of a specific asset, benchmark asset, market or interest rate (“reference measure”). The purchase of structured notes exposes the Fund to the credit risk of the issuer of the structured product. Structured notes may be leveraged, increasing the volatility of each structured note’s value relative to the change in the reference measure. Structured notes may also be less liquid and more difficult to price accurately than less complex securities and instruments or more traditional debt securities. Subsidiary Risk — By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The commodity-related instruments held by the Subsidiary are generally similar to those that are permitted to be held by the Fund and are subject to the same risks that apply to similar investments if held directly by the Fund (see “Commodities Related Investment Risks” above). There can be no assurance that the investment objective of the Subsidiary will be achieved. The Subsidiary is not registered under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and, unless otherwise noted in this prospectus, is not subject to all the investor protections of the Investment Company Act. However, the Fund wholly owns and controls the Subsidiary, and the Fund and the Subsidiary are both managed by BlackRock, making it unlikely that the Subsidiary will take action contrary to the interests of the Fund and its shareholders. Changes in the laws of the United States and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in this prospectus and the Statement of Additional Information (“SAI”) and could adversely affect the Fund. Warrants Risk — If the price of the underlying stock does not rise above the exercise price before the warrant expires, the warrant generally expires without any value and the Fund will lose any amount it paid for the warrant. Thus, investments in warrants may involve substantially more risk than investments in common stock. Warrants may trade in the same markets as their underlying stock; however, the price of the warrant does not necessarily move with the price of the underlying stock.
Risk Lose Money [Text]	rr_RiskLoseMoney	You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. Class K Shares do not have a performance history as of the date of this prospectus. As a result, the chart and the table give you a picture of the long-term performance for Institutional Shares of the Fund, which are not offered in this prospectus. The performance of Class K Shares would be substantially similar to Institutional Shares and differ only to the extent that Institutional Shares and Class K Shares have different expenses. The actual returns of Class K Shares would have been higher than those of Institutional Shares because Class K Shares have lower expenses than Institutional Shares. The table compares the Fund’s performance to that of the FTSE World Index, the S&P 500 Index, the FTSE World (ex US) Index, the BofA Merrill Lynch Current 5-Year US Treasury Index, the Citigroup Non-US Dollar World Government Bond Index and the Reference Benchmark, which are relevant to the Fund because they have characteristics similar to the Fund’s investment strategies. To the extent that dividends and distributions have been paid by the Fund, the performance information for the Fund in the chart and table assumes reinvestment of the dividends and distributions. As with all such investments, past performance (before and after taxes) is not an indication of future results. The table includes all applicable fees. If the Fund’s investment manager and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund’s returns would have been lower. Updated information on the Fund’s performance, including its current net asset value, can be obtained by visiting http://www.blackrock.com/funds or can be obtained by phone at 800-882-0052.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	Class K Shares do not have a performance history as of the date of this prospectus.
Performance Additional Market Index [Text]	rr_PerformanceAdditionalMarketIndex	The table compares the Fund’s performance to that of the FTSE World Index, the S&P 500 Index, the FTSE World (ex US) Index, the BofA Merrill Lynch Current 5-Year US Treasury Index, the Citigroup Non-US Dollar World Government Bond Index and the Reference Benchmark, which are relevant to the Fund because they have characteristics similar to the Fund’s investment strategies.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-882-0052
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	http://www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance (before and after taxes) is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Institutional Shares ANNUAL TOTAL RETURNS BlackRock Global Allocation Fund As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the ten-year period shown in the bar chart, the highest return for a quarter was 12.15% (quarter ended June 30, 2009) and the lowest return for a quarter was –12.13% (quarter ended September 30, 2008). The year-to-date return as of March 31, 2016 was –0.45%.
Bar Chart, Returns for Class Not Offered in Prospectus [Text]	rr_BarChartReturnsForClassNotOfferedInProspectus	Class K Shares do not have a performance history as of the date of this prospectus. As a result, the chart and the table give you a picture of the long-term performance for Institutional Shares of the Fund, which are not offered in this prospectus.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/15 Average Annual Total Returns
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using the historical highest 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 the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	After-tax returns are calculated using the historical highest individual Federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
BLACKROCK GLOBAL ALLOCATION FUND, INC. | Class K Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.75%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses of the Fund	rr_Component1OtherExpensesOverAssets	0.04%	[1]
Other Expenses of the Subsidiary	rr_Component2OtherExpensesOverAssets	0.01%	[2]
Other Expenses	rr_OtherExpensesOverAssets	0.05%	[1],[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.80%
1 Year	rr_ExpenseExampleYear01	$ 82
3 Years	rr_ExpenseExampleYear03	255
5 Years	rr_ExpenseExampleYear05	444
10 Years	rr_ExpenseExampleYear10	$ 990
BLACKROCK GLOBAL ALLOCATION FUND, INC. | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
2006	rr_AnnualReturn2006	16.18%	[3]
2007	rr_AnnualReturn2007	17.00%
2008	rr_AnnualReturn2008	(20.35%)
2009	rr_AnnualReturn2009	21.99%
2010	rr_AnnualReturn2010	10.15%
2011	rr_AnnualReturn2011	(3.43%)
2012	rr_AnnualReturn2012	10.33%
2013	rr_AnnualReturn2013	14.71%
2014	rr_AnnualReturn2014	2.15%
2015	rr_AnnualReturn2015	(0.83%)
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Mar. 31, 2016
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(0.45%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	12.15%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(12.13%)
1 Year	rr_AverageAnnualReturnYear01	(0.83%)
5 Years	rr_AverageAnnualReturnYear05	4.37%
10 Years	rr_AverageAnnualReturnYear10	6.06%	[3]
BLACKROCK GLOBAL ALLOCATION FUND, INC. | Return After Taxes on Distributions | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(3.08%)
5 Years	rr_AverageAnnualReturnYear05	2.72%
10 Years	rr_AverageAnnualReturnYear10	4.53%	[3]
BLACKROCK GLOBAL ALLOCATION FUND, INC. | Return After Taxes on Distributions and Sale of Shares | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.16%
5 Years	rr_AverageAnnualReturnYear05	3.13%
10 Years	rr_AverageAnnualReturnYear10	4.47%	[3]
BLACKROCK GLOBAL ALLOCATION FUND, INC. | FTSE World Index (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.37%)
5 Years	rr_AverageAnnualReturnYear05	7.10%
10 Years	rr_AverageAnnualReturnYear10	5.49%	[3]
BLACKROCK GLOBAL ALLOCATION FUND, INC. | Standard & Poor's (S&P) 500 Index (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.38%
5 Years	rr_AverageAnnualReturnYear05	12.57%
10 Years	rr_AverageAnnualReturnYear10	7.31%	[3]
BLACKROCK GLOBAL ALLOCATION FUND, INC. | FTSE World (ex US) Index (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(4.16%)
5 Years	rr_AverageAnnualReturnYear05	2.10%
10 Years	rr_AverageAnnualReturnYear10	3.59%	[3]
BLACKROCK GLOBAL ALLOCATION FUND, INC. | BofA Merrill Lynch Current 5-Year US Treasury Index (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.49%
5 Years	rr_AverageAnnualReturnYear05	2.63%
10 Years	rr_AverageAnnualReturnYear10	4.41%	[3]
BLACKROCK GLOBAL ALLOCATION FUND, INC. | Citigroup Non-US Dollar World Government Bond Index (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(5.54%)
5 Years	rr_AverageAnnualReturnYear05	(1.30%)
10 Years	rr_AverageAnnualReturnYear10	3.05%	[3]
BLACKROCK GLOBAL ALLOCATION FUND, INC. | Reference Benchmark (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(0.78%)
5 Years	rr_AverageAnnualReturnYear05	5.58%
10 Years	rr_AverageAnnualReturnYear10	5.46%	[3]

[1] Other Expenses are based on estimated amounts for the current fiscal year.

[2] Other Expenses include expenses of the BlackRock Cayman Global Allocation Fund I, Ltd. (the “Subsidiary”) for the Fund’s last fiscal year.

[3] In 2006, a portion of the Fund’s total investment return consisted of a payment by the Fund’s former investment manager in order to resolve a regulatory issue relating to an investment.