497

SIDLEY AUSTIN LLP 787 SEVENTH AVENUE NEW YORK, NY 10019 (212) 839 5300 (212) 839 5599 FAX BEIJING BRUSSELS CHICAGO DALLAS FRANKFURT GENEVA HONG KONG HOUSTON LONDON   FOUNDED 1866 LOS ANGELES NEW YORK PALO ALTO SAN FRANCISCO SHANGHAI SINGAPORE SYDNEY TOKYO WASHINGTON, D.C.

February 22, 2013

VIA EDGAR

Securities and Exchange Commission

100 F Street, NE

Washington, DC 20549

Re: BlackRock Global Opportunities Portfolio, BlackRock International

Opportunities Portfolio and BlackRock Managed Volatility Portfolio, each a series of BlackRock Funds^SM

(File Nos. 33-26305, 811-05742)

Ladies and Gentlemen:

On behalf of BlackRock Funds^SM, attached for filing are exhibits containing interactive data format risk/return summary information that mirrors the risk/return summary information in the Prospectuses of BlackRock Global Opportunities Portfolio, BlackRock International Opportunities Portfolio and BlackRock Managed Volatility Portfolio (the “Funds”), dated January 28, 2013, as filed pursuant to Rule 497(e) under the Securities Act of 1933, on February 4, 2013 (the “497 Filing”). The purpose of this filing is to submit the 497 Filing in XBRL for the Funds.

Any questions or comments on the 497 Filing should be directed to the undersigned at (212) 839-5583.

Very truly yours,

/s/ Ellen W. Harris

Ellen W. Harris

Enclosures

cc: Benjamin Archibald, Esq.

BlackRock Advisors, LLC

Sidley Austin (NY) LLP is a Delaware limited liability partnership doing business as Sidley Austin LLP and practicing in affiliation with other Sidley Austin partnerships.

XML

BLACKROCK MANAGED VOLATILITY PORTFOLIO

Fund Overview

Investment Objective

The investment objective of BlackRock Managed Volatility Portfolio, formerly BlackRock Asset Allocation Portfolio (“Managed Volatility Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek total return.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold Class R Shares of Managed Volatility Portfolio.

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses		BLACKROCK MANAGED VOLATILITY PORTFOLIO Class R Shares
Management Fee	[1]	0.55%
Distribution and/or Service (12b-1) Fees		0.50%
Other Expenses		0.43%
Interest Expense		0.01%
Miscellaneous Other Expenses	[2]	0.42%
Acquired Fund Fees and Expenses		0.05%
Total Annual Fund Operating Expenses		1.53%
Fee Waivers and/or Expense Reimbursements	[3]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[3]	1.53%

Example:

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:

Expense Example (USD $)	1 Year	3 Years
BLACKROCK MANAGED VOLATILITY PORTFOLIO Class R Shares	156	483

Portfolio Turnover:

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover 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 324% of the average value of its portfolio.

Principal Investment Strategies of the Fund

Managed Volatility Portfolio uses an asset allocation strategy, investing varying percentages of its portfolio in three major categories: stocks, bonds and money market instruments. The Fund has wide flexibility in the relative weightings given to each category.

The Fund may also invest a significant portion of its assets in affiliated and unaffiliated ETFs and mutual funds. See “Information About the ETFs and Mutual Funds.”

With respect to its equity investments, the Fund may invest in ETFs, mutual funds or individual equity securities to an unlimited extent. The Fund, the ETFs and the mutual funds may invest in common stock, preferred stock, securities convertible into common stock, non-convertible preferred stock and depositary receipts. The Fund, the ETFs and the mutual funds may invest in securities of both U.S. and non-U.S. issuers without limit, which can be U.S. dollar-based or non-U.S. dollar-based and may be currency hedged or unhedged. The Fund, the ETFs and the mutual funds may invest in securities of companies of any market capitalization.

With respect to its fixed-income investments, the Fund may invest in ETFs, mutual funds or individual fixed-income securities to an unlimited extent. The Fund, the ETFs and the mutual funds may invest in a portfolio of fixed-income securities such as corporate bonds and notes, commercial and residential mortgage-backed securities (bonds that are backed by a mortgage loan or pools of loans secured either by commercial property or residential mortgages, as applicable), collateralized mortgage obligations (bonds that are backed by cash flows from pools of mortgages and may have multiple classes with different payment rights and protections), collateralized debt obligations, asset-backed securities, convertible securities, debt obligations of governments and their sub-divisions (including those of non-U.S. governments), other floating or variable rate obligations, municipal obligations and zero coupon debt securities. The Fund, the ETFs and the mutual funds may also invest a significant portion of their assets in non-investment grade bonds (junk bonds or distressed securities), non-investment grade bank loans, foreign bonds (both U.S. dollar- and non-U.S. dollar-denominated) and bonds of emerging market issuers. The Fund, the ETFs and the mutual funds may invest in non-U.S. dollar-denominated bonds on a currency hedged or unhedged basis.

With respect to its cash investments, the Fund may hold high quality money market securities, including short term U.S. Government securities, U.S. Government agency securities, securities issued by U.S. Government-sponsored enterprises and U.S. Government instrumentalities, bank obligations, commercial paper, including asset-backed commercial paper, corporate notes and repurchase agreements. The Fund may invest a significant portion of its assets in money market funds, including those advised by BlackRock or its affiliates.

The Fund may invest in derivatives, including, but not limited to, interest rate, total return and credit default swaps, indexed and inverse floating rate securities, options, futures, options on futures and swaps and foreign currency transactions (including swaps), for hedging purposes, as well as to increase the return on its portfolio investments. The Fund may seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as reverse repurchase agreements or dollar rolls). The Fund may also use forward foreign currency exchange contracts (obligations to buy or sell a currency at a set rate in the future) to hedge against movement in the value of non-U.S. currencies. The ETFs and the mutual funds may, to varying degrees, also invest in derivatives.

The Fund may invest in U.S. and non-U.S. real estate investment trusts (“REITs”), structured products (including, but not limited to, structured notes, credit linked notes and participation notes, or other instruments evidencing interests in special purpose vehicles, trusts, or other entities that hold or represent interests in fixed-income securities) and floating rate securities (such as bank loans).

The Fund incorporates a volatility control process that seeks to reduce risk when portfolio volatility is expected to deviate from the Fund’s targeted total return volatility of 10% over a one-year period. Volatility is a statistical measurement of the magnitude of up and down fluctuations in the value of a financial instrument or index over time. Volatility may result in rapid and dramatic price swings. While BlackRock attempts to manage the Fund’s volatility exposure to stabilize performance, there can be no guarantee that the Fund will reach its target volatility. The Fund will adjust its asset allocation in response to periods of high or low expected volatility. The Fund may without limitation allocate assets into cash or short-term fixed-income securities, and away from riskier assets such as equity and high yield fixed-income securities. When volatility decreases, the Fund may move assets out of cash and back into riskier securities. At any given time, the Fund may be invested entirely in equities, fixed-income or cash. As part of its attempt to manage the Fund’s volatility exposure, during certain periods the Fund may make significant investments in index futures or other derivative instruments designed to reduce the Fund’s exposure to portfolio volatility. The Fund may engage in active and frequent trading of portfolio securities to achieve its primary investment strategies.

Investment Risks

Risk is inherent in all investing. The value of your investment in Managed Volatility Portfolio, 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 principal risks set forth below are the principal risks of investing in the Fund and/or the ETFs and the mutual funds (each, an “Underlying Fund”).

Principal Risks of the Fund’s Fund of Funds Structure

• Affiliated Fund Risk — In managing the Fund, BlackRock will have authority to select and substitute ETFs or mutual funds. BlackRock may be subject to potential conflicts of interest in selecting ETFs or mutual funds because the fees paid to BlackRock by some ETFs or mutual funds are higher than the fees paid by other ETFs or mutual funds. However, BlackRock is a fiduciary to the Fund and is legally obligated to act in the Fund’s best interests when selecting ETFs and mutual funds.

• Allocation Risk — The Fund’s ability to achieve its investment objective depends upon BlackRock’s skill in determining the Fund’s strategic asset class allocation and in selecting the best mix of ETFs, mutual funds and direct investments. There is a risk that BlackRock’s evaluations and assumptions regarding asset classes or ETFs or mutual funds may be incorrect in view of actual market conditions.

• Investments in ETFs and Other Mutual Funds Risk — The Fund’s net asset value will change with changes in the value of the ETFs, mutual funds and other securities in which it invests. As with other investments, investments in other investment companies, including ETFs, are subject to market risk and, for non-index strategies, selection risk. In addition, if the Fund acquires shares of investment companies, including ETFs, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies. If the Fund acquires shares of affiliated mutual funds, shareholders bear both their proportionate share of expenses in the Fund (excluding management and advisory fees) and, indirectly, the expenses of the mutual funds. To the extent the Fund is held by an affiliated fund, the ability of the Fund itself to hold other investment companies may be limited.
  
  One ETF or mutual fund may buy the same securities that another ETF or mutual fund sells. In addition, the Fund may buy the same securities that an ETF or mutual fund sells, or vice-versa. If this happens, an investor in the Fund would indirectly bear the costs of these transactions without accomplishing the intended investment purpose. Also, an investor in the Fund may receive taxable gains from portfolio transactions by an ETF or mutual fund, as well as taxable gains from transactions in shares of the ETF or mutual fund by the Fund. Certain of the ETFs or mutual funds may hold common portfolio securities, thereby reducing the diversification benefits of the Fund.

Principal ETF-Specific Risks

• Cash Transaction Risk — Certain ETFs intend to effect creations and redemptions principally for cash, rather than primarily in-kind because of the nature of the ETF’s investments. Investments in such ETFs may be less tax efficient than investments in ETFs that effect creations and redemptions in-kind.

• Management Risk — If an ETF does not fully replicate the underlying index, it is subject to the risk that the manager’s investment management strategy may not produce the intended results.

• Passive Investment Risk — ETFs purchased by the Fund are not actively managed and may be affected by a general decline in market segments relating to their respective indices. An ETF typically invests in securities included in, or representative of, its index regardless of their investment merits and does not attempt to take defensive positions in declining markets.

• Representative Sampling Risk — When an ETF deviates from a full replication indexing strategy to utilize a representative sampling strategy, the ETF is subject to an increased risk of tracking error, in that the securities selected in the aggregate for the ETF may not have an investment profile similar to those of its index.

• Shares of an ETF May Trade at Prices Other Than Net Asset Value — The trading prices of an ETF’s shares fluctuate continuously throughout trading hours based on market supply and demand rather than net asset value. The trading prices of an ETF’s shares may deviate significantly from net asset value during periods of market volatility. Any of these factors may lead to an ETF’s shares trading at a premium or discount to net asset value. However, because shares can be created and redeemed in Creation Units, which are aggregated blocks of shares that authorized participants who have entered into agreements with the ETF’s distributor can purchase or redeem directly from the ETF, at net asset value, large discounts or premiums to the net asset value of an ETF are not likely to be sustained over the long term. If a shareholder purchases at a time when the market price is at a premium to the net asset value or sells at a time when the market price is at a discount to the net asset value, the shareholder may sustain losses.

• Tracking Error Risk — Imperfect correlation between an ETF’s portfolio securities and those in its index, rounding of prices, the timing of cash flows, the ETF’s size, changes to the index and regulatory requirements may cause tracking error, which is the divergence of an ETF’s performance from that of its underlying index. This risk may be heightened during times of increased market volatility or other unusual market conditions. Tracking error also may result because an ETF incurs fees and expenses while its underlying index does not.

Other Principal Risks of Investing in the Fund and/or an Underlying Fund

• Collateralized Debt Obligations Risk — The pool of high yield securities underlying collateralized debt obligations is typically separated into groupings called tranches representing different degrees of credit quality. The higher quality tranches have greater degrees of protection and pay lower interest rates. The lower tranches, with greater risk, pay higher interest rates.

• Concentration Risk — To the extent that the Fund’s or an Underlying Fund’s portfolio reflects concentration in the securities of issuers in a particular region, market, industry, group of industries, country, group of countries, sector or asset class, the Fund or the Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that region, market, industry, group of industries, country, group of countries, sector or asset class.

• 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, wide bid/ask spreads and extended trade settlement periods. The corporate loans in which the Fund or an Underlying Fund invests are usually rated below investment grade.

• Counterparty Risk — The counterparty to an over-the-counter derivatives contract or a borrower of the Fund’s or an Underlying Fund’s securities may be unable or unwilling to make timely principal, interest or settlement payments, or otherwise to honor its obligations.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. The degree of credit risk depends on the issuer’s financial condition and on the terms of the securities.

• Debt Securities Risk — Debt securities, such as bonds, involve credit risk. Debt securities are also subject to interest rate risk.

• Derivatives Risk — The Fund’s or an Underlying Fund’s use of derivatives may reduce the Fund’s or the Underlying Fund’s returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s or an Underlying Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or an Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or the Underlying Fund to losses and could make derivatives more difficult for the Fund or the Underlying Fund to value accurately. Derivatives may give rise to a form of leverage and may expose the Fund or an Underlying Fund to greater risk and increase its costs. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation is not yet known and may not be known for some time. New regulation may make derivatives more costly, may limit the availability of derivatives, or may otherwise adversely affect the value or performance of derivatives.

• Distressed Securities Risk — Distressed securities are speculative and involve substantial risks in addition to the risks of investing in junk bonds. The Fund and the Underlying Funds 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.

• Dollar Rolls Risk — Dollar rolls involve the risk that the market value of the securities that the Fund or an Underlying Fund is committed to buy may decline below the price of the securities the Fund or the Underlying Fund has sold. These transactions may involve leverage.

• 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.

• Extension Risk — When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

• Foreign Securities Risk — Foreign investments often involve special risks not present in U.S. investments that can increase the chances that the Fund or an Underlying Fund will lose money. These risks include:
  
  — The Fund and the Underlying Funds generally hold their 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 or an Underlying 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, including countries that do not use the Euro. These events may affect the value and liquidity of certain of the Fund’s or an Underlying Fund’s investments.

• High Portfolio Turnover Risk — High portfolio turnover (more than 100%) may result in increased transaction costs to the Fund or an Underlying Fund and potentially higher capital gains or losses for shareholders. The effects of higher than normal portfolio turnover may adversely affect Fund or Underlying Fund performance.

• Indexed and Inverse Securities Risk — Certain indexed and inverse securities have greater sensitivity to changes in interest rates or index levels than other securities, and the Fund’s or an Underlying Fund’s investment in such instruments may decline significantly in value if interest rates or index levels move in a way Fund or Underlying Fund management does not anticipate.

• Inflation Indexed Bonds Risk — The principal value of an investment is not protected or otherwise guaranteed by virtue of the Fund’s or an Underlying Fund’s investments in inflation-indexed bonds.
  
  Inflation-indexed bonds are fixed-income securities whose principal value is periodically adjusted according to the rate of inflation. If the index measuring inflation falls, the principal value of inflation-indexed bonds will be adjusted downward, and consequently the interest payable on these securities (calculated with respect to a smaller principal amount) will be reduced.
  
  Repayment of the original bond principal upon maturity (as adjusted for inflation) is guaranteed in the case of U.S. Treasury inflation-indexed bonds. For bonds that do not provide a similar guarantee, the adjusted principal value of the bond repaid at maturity may be less than the original principal value.
  
  The value of inflation-indexed bonds is expected to change in response to changes in real interest rates. Real interest rates are tied to the relationship between nominal interest rates and the rate of inflation. If nominal interest rates increase at a faster rate than inflation, real interest rates may rise, leading to a decrease in value of inflation-indexed bonds. Short-term increases in inflation may lead to a decline in value. Any increase in the principal amount of an inflation-indexed bond will be considered taxable ordinary income, even though investors do not receive their principal until maturity.
  
  Periodic adjustments for inflation to the principal amount of an inflation-indexed bond may give rise to original issue discount, which will be includable in the Fund’s or an Underlying Fund’s gross income. Due to original issue discount, the Fund or an Underlying Fund may be required to make annual distributions to shareholders that exceed the cash received, which may cause the Fund or the Underlying Fund to liquidate certain investments when it is not advantageous to do so. Also, if the principal value of an inflation-indexed bond is adjusted downward due to deflation, amounts previously distributed in the taxable year may be characterized in some circumstances as a return of capital.

• Interest Rate Risk — 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. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

• Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion and value investments have performed better during periods of economic recovery. Therefore, these investment styles may over time go in and out of favor. At times when the investment style used by the Fund or Underlying Fund is out of favor, the Fund or Underlying Fund may underperform other funds that use different investment styles.

• 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 or Underlying 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 or an Underlying Fund to greater risk and increase its costs. The use of leverage may cause the Fund or an Underlying 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 or an Underlying Fund’s portfolio will be magnified when the Fund or the Underlying Fund uses leverage.

• Liquidity Risk — Liquidity risk exists when particular investments are difficult to purchase or sell. The Fund’s or an Underlying Fund’s investments in illiquid securities may reduce the returns of the Fund or the Underlying Fund because it may be difficult to sell the illiquid securities at an advantageous time or price. To the extent that the Fund’s or an Underlying Fund’s principal investment strategies involve derivatives or securities with substantial market and/or credit risk, the Fund will tend to have the greatest exposure to liquidity risk. Liquid investments may become illiquid after purchase by the Fund or an Underlying Fund, particularly during periods of market turmoil. Illiquid investments may be harder to value, especially in changing markets, and if the Fund or the Underlying Fund is forced to sell these investments to meet redemption requests or for other cash needs, the Fund or the Underlying Fund may suffer a loss. In addition, when there is illiquidity in the market for certain securities, the Fund or an Underlying Fund, due to limitations on illiquid investments, may be subject to purchase and sale restrictions.

• Market Risk and Selection Risk — Market risk is the risk that one or more markets in which the Fund or an Underlying 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 or Underlying 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.

• Municipal Securities Risks — Municipal securities risks include the ability of the issuer to repay the obligation, the relative lack of information about certain issuers of municipal securities, and the possibility of future legislative changes which could affect the market for and value of municipal securities. These risks include:
  
  General Obligation Bonds Risks — Timely payments depend on the issuer’s credit quality, ability to raise tax revenues and ability to maintain an adequate tax base.
  
  Revenue Bonds Risks — These payments depend on the money earned by the particular facility or class of facilities, or the amount of revenues derived from another source.
  
  Private Activity Bonds Risks — Municipalities and other public authorities issue private activity bonds to finance development of industrial facilities for use by a private enterprise. The private enterprise pays the principal and interest on the bond, and the issuer does not pledge its faith, credit and taxing power for repayment.
  
  Moral Obligation Bonds Risks — Moral obligation bonds are generally issued by special purpose public authorities of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral commitment, but not a legal obligation, of the state or municipality.
  
  Municipal Notes Risks — Municipal notes are shorter term municipal debt obligations. If there is a shortfall in the anticipated proceeds, the notes may not be fully repaid and the Fund or an Underlying Fund may lose money.
  
  Municipal Lease Obligations Risks — In a municipal lease obligation, the issuer agrees to make payments when due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease obligation, the lease obligation is secured by the leased property.

• Preferred Securities Risk — Preferred securities may pay fixed or adjustable rates of return. Preferred securities are subject to issuer-specific and market risks applicable generally to equity securities.

• Prepayment Risk — When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund or an Underlying Fund may have to invest the proceeds in securities with lower yields.

• Real Estate Related Securities Risks — 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 or an Underlying Fund’s real estate related investments are concentrated in one geographic area or in one property type, the Fund or the Underlying 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.

• Repurchase Agreements and Purchase and Sale Contracts Risks — If the other party to a repurchase agreement or purchase and sale contract defaults on its obligation under the agreement, the Fund or an Underlying Fund may suffer delays and incur costs or lose money in exercising its rights under the agreement. If the seller fails to repurchase the security in either situation and the market value of the security declines, the Fund or an Underlying Fund may lose money.

• Reverse Repurchase Agreements Risk — Reverse repurchase agreements involve the risk that the other party to the reverse repurchase agreement may fail to return the securities in a timely manner or at all. The Fund or an Underlying Fund could lose money if it is unable to recover the securities and the value of the collateral held by the Fund or the Underlying Fund, including the value of the investments made with cash collateral, is less than the value of securities. These events could also trigger adverse tax consequences to the Fund or an Underlying Fund.

• Risks of Loan Assignments and Participations — As the purchaser of an assignment, the Fund or an Underlying Fund typically succeeds to all the rights and obligations of the assigning institution and becomes a lender under the credit agreement with respect to the debt obligation; however, the Fund or an Underlying Fund may not be able unilaterally to enforce all rights and remedies under the loan and with regard to any associated collateral. Because assignments may be arranged through private negotiations between potential assignees and potential assignors, the rights and obligations acquired by the Fund or an Underlying Fund as the purchaser of an assignment may differ from, and be more limited than, those held by the assigning lender. In addition, if the loan is foreclosed, the Fund or an Underlying Fund could become part owner of any collateral and could bear the costs and liabilities of owning and disposing of the collateral. The Fund or an Underlying Fund may be required to pass along to a purchaser that buys a loan from the Fund or the Underlying Fund by way of assignment a portion of any fees to which the Fund or the Underlying Fund is entitled under the loan. In connection with purchasing participations, the Fund or an Underlying Fund generally will have no right to enforce compliance by the borrower with the terms of the loan agreement relating to the loan, nor any rights of set-off against the borrower, and the Fund or an Underlying Fund may not directly benefit from any collateral supporting the loan in which it has purchased the participation. As a result, the Fund or an Underlying Fund will be subject to the credit risk of both the borrower and the lender that is selling the participation. In the event of the insolvency of the lender selling a participation, the Fund or an Underlying Fund may be treated as a general creditor of the lender and may not benefit from any set-off between the lender and the borrower.

• Second Lien Loans Risk — Second lien loans generally are subject to similar risks as those associated with investments in senior loans. Because second lien loans are subordinated or unsecured and thus lower in priority of payment to senior loans, they are subject to the additional risk that the cash flow of the borrower and property securing the loan or debt, if any, may be insufficient to meet scheduled payments after giving effect to the senior secured obligations of the borrower.

• Senior Loans Risk —There is less readily available, reliable information about most senior loans than is the case for many other types of securities. An economic downturn generally leads to a higher non-payment rate, and a senior loan may lose significant value before a default occurs. Moreover, any specific collateral used to secure a senior loan may decline in value or become illiquid, which would adversely affect the senior loan’s value. No active trading market may exist for certain senior loans, which may impair the ability of the Fund or an Underlying Fund to realize full value in the event of the need to sell a senior loan and which may make it difficult to value senior loans. Although senior loans in which the Fund or an Underlying Fund will invest generally will be secured by specific collateral, there can be no assurance that liquidation of such collateral would satisfy the borrower’s obligation in the event of non-payment of scheduled interest or principal or that such collateral could be readily liquidated. To the extent that a senior loan is collateralized by stock in the borrower or its subsidiaries, such stock may lose all of its value in the event of the bankruptcy of the borrower. Uncollateralized senior loans involve a greater risk of loss. The senior loans in which the Fund or an Underlying Fund invests are usually rated below investment grade.

• Small Cap and Emerging Growth Securities Risks — 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 or an Underlying 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 or an Underlying 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.

• Structured Products Risk — Holders of structured products bear risks of the underlying investments, index or reference obligation and are subject to counterparty risk. The Fund or an Underlying Fund may have the right to receive payments only from the structured product, and generally does not have direct rights against the issuer or the entity that sold the assets to be securitized. Certain structured products may be thinly traded or have a limited trading market. In addition to the general risks associated with debt securities discussed herein, structured products carry additional risks, including, but not limited to: the possibility that distributions from collateral securities will not be adequate to make interest or other payments; the quality of the collateral may decline in value or default; and the possibility that the structured products are subordinate to other classes.

• Supranational Entities Risk — The Fund or an Underlying Fund may invest in obligations issued or guaranteed by the International Bank for Reconstruction and Development (the World Bank). If one or more stockholders of the World Bank fail to make necessary additional capital contributions, the entity may be unable to pay interest or repay principal on its debt securities, and the Fund or an Underlying Fund may lose money on such investments.

• Tender Option Bonds and Related Securities Risk — Investments in tender option bonds, residual interest tender option bonds and inverse floaters expose the Fund or an Underlying Fund to the same risks as investments in derivatives, as well as risks associated with leverage, described above, especially the risk of increased volatility. An investment in these securities may be subject to the risk of loss of principal. Residual interest tender option bonds and inverse floaters generally will underperform the market for fixed rate municipal securities in a rising interest rate environment.

• U.S. Government Mortgage-Related Securities Risk — There are a number of important differences among the agencies and instrumentalities of the U.S. Government that issue mortgage-related securities and among the securities that they issue. Mortgage-related securities guaranteed by the Government National Mortgage Association (“Ginnie Mae”) are guaranteed as to the timely payment of principal and interest by Ginnie Mae and such guarantee is backed by the full faith and credit of the United States. Ginnie Mae securities also are supported by the right of Ginnie Mae to borrow funds from the U.S. Treasury to make payments under its guarantee. Mortgage-related securities issued by The Federal National Mortgage Association (“Fannie Mae”) or The Federal Home Loan Mortgage Corporation (“Freddie Mac”) are solely the obligations of Fannie Mae or Freddie Mac, as the case may be, and are not backed by or entitled to the full faith and credit of the United States but are supported by the right of the issuer to borrow from the U.S. Treasury.

• U.S. Government Obligations Risk — Certain securities in which the Fund or an Underlying Fund may invest, including securities issued by certain U.S. Government agencies and U.S. Government sponsored enterprises, are not guaranteed by the U.S. Government or supported by the full faith and credit of the United States.

• Variable and Floating Rate Instrument Risk — The absence of an active market for these securities could make it difficult for the Fund or an Underlying Fund to dispose of them if the issuer defaults.

• 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 or an Underlying Fund loses any amount it paid for the warrant. Thus, investments in warrants may involve substantially more risk than investments in common stock.

• Zero Coupon Securities Risk — While interest payments are not made on such securities, holders of such securities are deemed to have received income (“phantom income”) annually, notwithstanding that cash may not be received currently. Some of these securities may be subject to substantially greater price fluctuations during periods of changing market interest rates than are comparable securities that pay interest currently. Longer term zero coupon bonds are more exposed to interest rate risk than shorter term zero coupon bonds.

Performance Information

Class R Shares do not have a performance history as of the date of this prospectus. As a result, the chart and table show you the long-term performance of Managed Volatility Portfolio for Investor A Shares, which are not offered in this prospectus. Investor A Shares would have annual returns substantially similar to Class R Shares differing only to the extent that Investor A and Class R Shares have different expenses. The actual return of Class R Shares would generally be lower than that of Investor A Shares because Class R Shares are subject to higher distribution and/or service (12b-1) fees than Investor A Shares.

Effective May 15, 2012, the Fund changed its investment strategy to invest a significant portion of its assets in ETFs and, to a lesser extent, in mutual funds and directly in securities. Performance for the periods prior to May 15, 2012 shown below is based on the investment strategy utilized by the Fund, which focused on investing directly in securities.

On January 31, 2005, the Fund reorganized with the State Street Research Asset Allocation Fund (the “SSR Fund”), which had investment objectives and strategies similar to the Fund. For periods prior to January 31, 2005, the chart and table show performance information for the SSR Fund. 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. The table compares the Fund’s performance to that of the MSCI All Country World Index (the “MSCI ACWI Index”), the Citigroup World Government Bond Index (hedged into USD) (the “Citigroup WGBI (hedged into USD)”), the Barclays U.S. Aggregate Bond Index and two customized weighted indices comprised of the returns of the MSCI ACWI Index, the Citigroup WGBI (hedged into USD) and the Barclays U.S. Aggregate Bond Index in the percentages and combinations set forth in the table. Effective May 15, 2012, the Fund changed one of the components making up the customized weighted index from the Barclays U.S. Aggregate Bond Index to the Citigroup WGBI (hedged into USD). Fund management believes that the Citigroup WGBI (hedged into USD) better reflects the Fund’s increasing global exposure. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If BlackRock 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 results can be obtained by visiting http://www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Investor A Shares
ANNUAL TOTAL RETURNS
BlackRock Managed Volatility Portfolio
As of 12/31

During the ten-year period shown in the bar chart, the highest return for a quarter was 13.66% (quarter ended September 30, 2009) and the lowest return for a quarter was –13.17% (quarter ended December 31, 2008).

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns BLACKROCK MANAGED VOLATILITY PORTFOLIO	1 Year	5 Years		10 Years
Investor A	6.12%	1.47%	[1]	6.69%	[1]
Investor A Return After Taxes on Distributions	4.80%	0.84%	[1]	5.75%	[1]
Investor A Return After Taxes on Distributions and Sale of Shares	4.65%	1.05%	[1]	5.54%	[1]
MSCI ACWI Index (Reflects no deduction for fees, expenses or taxes)	16.13%	(1.16%)	[1]	8.11%	[1]
Citigroup WGBI (hedged into USD) (Reflects no deduction for fees, expenses or taxes)	4.50%	4.68%	[1]	4.41%	[1]
60% MSCI ACWI Index/40% Citigroup WGBI (hedged into USD) (Reflects no deduction for fees, expenses or taxes)	11.61%	1.79%	[1]	7.03%	[1]
Barclays U.S. Aggregate Bond Index (Reflects no deduction for fees, expenses or taxes)	4.21%	5.95%	[1]	5.18%	[1]
60% MSCI ACWI Index/40% Barclays U.S. Aggregate Bond Index (Reflects no deduction for fees, expenses or taxes)	11.48%	2.20%	[1]	7.30%	[1]

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. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Class R Shares will vary.

[1] The Management Fee payable by the Fund is based on assets estimated to be attributable to the Fund's direct investments in fixed-income and equity securities and instruments, including exchange-traded funds ("ETFs") advised by BlackRock or other investment advisers, other investments and cash and cash equivalents (including money market funds). BlackRock has contractually agreed to waive the Management Fee on assets estimated to be attributed to the Fund's investments in other equity and fixed-income mutual funds managed by BlackRock or its affiliates (the "mutual funds").

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

[3] As described in the "Management of the Fund" section of the Fund's prospectus on pages 76-80, BlackRock has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 1.81% of average daily net assets until February 1, 2014. The Fund may have to repay some of these waivers and/or reimbursements to BlackRock in the following two years. The agreement may be terminated upon 90 days' notice by a majority of the non-interested Trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund.

[1] A portion of the Fund's total return was attributable to proceeds received in the fiscal year ended September 30, 2009 in settlement of litigation.

[1] A portion of the Fund's total return was attributable to proceeds received in the fiscal year ended September 30, 2009 in settlement of litigation.

XML

BLACKROCK INTERNATIONAL OPPORTUNITIES PORTFOLIO

Fund Overview

Key Facts About BlackRock International Opportunities Portfolio

Investment Objective

The investment objective of BlackRock International Opportunities Portfolio (“International Opportunities” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold Class R Shares of International Opportunities.

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses		BLACKROCK INTERNATIONAL OPPORTUNITIES PORTFOLIO Class R Shares
Management Fee		0.98%
Distribution and/or Service (12b-1) Fees		0.50%
Other Expenses	[1]	0.34%
Acquired Fund Fees and Expenses		0.01%
Total Annual Fund Operating Expenses		1.83%
Fee Waivers and/or Expense Reimbursements	[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[2]	1.83%

Example:

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:

Expense Example (USD $)	1 Year	3 Years
BLACKROCK INTERNATIONAL OPPORTUNITIES PORTFOLIO Class R Shares	186	576

Portfolio Turnover:

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover 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 99% of the average value of its portfolio.

Principal Investment Strategies of the Fund

Under normal market conditions, International Opportunities invests at least 80% of its net assets in equity securities issued by foreign companies of any market capitalization. The Fund may invest up to 40% of its net assets in stocks of issuers in emerging market countries.

The Fund seeks to buy primarily common stock but can also invest in preferred stock and convertible securities. From time to time the Fund may invest in shares of companies through initial public offerings (“IPOs”).

The Fund may, when consistent with the Fund’s investment objective, buy or sell options or futures on a security or an index of securities and may buy options on a currency or a basket of currencies, or enter into foreign currency transactions, including swaps (collectively, commonly known as derivatives). The Fund typically uses derivatives as a substitute for taking a position in the underlying asset and/or as part of a strategy designed to reduce exposure to other risks, such as currency risk. The Fund may also use derivatives to enhance returns, in which case their use would involve leveraging risk. The Fund may seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as reverse repurchase agreements or dollar rolls). The Fund may also use forward foreign currency exchange contracts (obligations to buy or sell a currency at a set rate in the future).

Principal Risks of Investing in the Fund

Risk is inherent in all investing. The value of your investment in International Opportunities, 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.

• 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.

• Derivatives Risk — The Fund’s use of derivatives may reduce the Fund’s returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. 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. Derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation is not yet known and may not be known for some time. New regulation may make derivatives more costly, may limit the availability of derivatives, or may otherwise adversely affect the value or performance of derivatives.

• 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, including countries that do not use the Euro. These events may affect the value and liquidity of certain of the Fund’s investments.

• Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion. Therefore, the growth investment style may over time go in and out of favor. At times when the investment style used by the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.

• 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.

• “New Issues” Risk — “New Issues” are initial public offerings of equity securities of U.S. and non-U.S. issuers. Securities issued in IPOs have no trading history, and information about the companies may be available for very limited periods. In addition, the prices of securities sold in IPOs may be highly volatile or may decline shortly after the initial public offering.

• Small Cap Securities Risk — Small cap 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.

Performance Information

Class R Shares do not have a performance history as of the date of this prospectus. As a result, the chart and table show you the long-term performance of International Opportunities for Investor A Shares, which are not offered in this prospectus. Investor A Shares would have annual returns substantially similar to Class R Shares differing only to the extent that Investor A and Class R Shares have different expenses. The actual return of Class R Shares would generally be lower than that of Investor A Shares because Class R Shares are subject to higher distribution and/or service (12b-1) fees than Investor A Shares.

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. The table compares the Fund’s performance to that of the MSCI All Country World Index Ex-U.S. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If BlackRock and its affiliates had not waived or reimbursed certain Fund expenses during those periods, the Fund’s returns would have been lower. Updated information on the Fund’s results can be obtained by visiting http://www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Investor A Shares
ANNUAL TOTAL RETURNS
BlackRock International Opportunities Portfolio
As of 12/31

During the ten-year period shown in the bar chart, the highest return for a quarter was 28.03% (quarter ended June 30, 2009) and the lowest return for a quarter was –24.50% (quarter ended September 30, 2008).

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns BLACKROCK INTERNATIONAL OPPORTUNITIES PORTFOLIO	1 Year	5 Years	10 Years
Investor A	11.83%	(3.77%)	11.98%
Investor A Return After Taxes on Distributions	11.59%	(3.81%)	11.19%
Investor A Return After Taxes on Distributions and Sale of Shares	8.00%	(3.07%)	10.68%
MSCI All Country World Index Ex-U.S. (Reflects no deduction for fees, expenses or taxes)	16.83%	(2.89%)	9.74%

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. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Class R Shares will vary.

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

[2] As described in the "Management of the Funds" section of the Fund's prospectus on pages 48-55, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 2.18% of average daily net assets until February 1, 2014. The Fund may have to repay some of these waivers and/or reimbursements to BlackRock in the following two years. The agreement may be terminated upon 90 days' notice by a majority of the non-interested trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jan. 28, 2013
BLACKROCK INTERNATIONAL OPPORTUNITIES PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock International Opportunities Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock International Opportunities Portfolio (“International Opportunities” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek long-term capital appreciation.
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 R Shares of International Opportunities.
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	February 1, 2014
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 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 99% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	99.00%
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	Under normal market conditions, International Opportunities invests at least 80% of its net assets in equity securities issued by foreign companies of any market capitalization. The Fund may invest up to 40% of its net assets in stocks of issuers in emerging market countries. The Fund seeks to buy primarily common stock but can also invest in preferred stock and convertible securities. From time to time the Fund may invest in shares of companies through initial public offerings (“IPOs”). The Fund may, when consistent with the Fund’s investment objective, buy or sell options or futures on a security or an index of securities and may buy options on a currency or a basket of currencies, or enter into foreign currency transactions, including swaps (collectively, commonly known as derivatives). The Fund typically uses derivatives as a substitute for taking a position in the underlying asset and/or as part of a strategy designed to reduce exposure to other risks, such as currency risk. The Fund may also use derivatives to enhance returns, in which case their use would involve leveraging risk. The Fund may seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as reverse repurchase agreements or dollar rolls). The Fund may also use forward foreign currency exchange contracts (obligations to buy or sell a currency at a set rate in the future).
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 International Opportunities, 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. 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. Derivatives Risk — The Fund’s use of derivatives may reduce the Fund’s returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. 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. Derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation is not yet known and may not be known for some time. New regulation may make derivatives more costly, may limit the availability of derivatives, or may otherwise adversely affect the value or performance of derivatives. 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, including countries that do not use the Euro. These events may affect the value and liquidity of certain of the Fund’s investments. Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion. Therefore, the growth investment style may over time go in and out of favor. At times when the investment style used by the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles. 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. “New Issues” Risk — “New Issues” are initial public offerings of equity securities of U.S. and non-U.S. issuers. Securities issued in IPOs have no trading history, and information about the companies may be available for very limited periods. In addition, the prices of securities sold in IPOs may be highly volatile or may decline shortly after the initial public offering. Small Cap Securities Risk — Small cap 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.
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	Class R Shares do not have a performance history as of the date of this prospectus. As a result, the chart and table show you the long-term performance of International Opportunities for Investor A Shares, which are not offered in this prospectus. Investor A Shares would have annual returns substantially similar to Class R Shares differing only to the extent that Investor A and Class R Shares have different expenses. The actual return of Class R Shares would generally be lower than that of Investor A Shares because Class R Shares are subject to higher distribution and/or service (12b-1) fees than Investor A Shares. 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. The table compares the Fund’s performance to that of the MSCI All Country World Index Ex-U.S. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If BlackRock and its affiliates had not waived or reimbursed certain Fund expenses during those periods, the Fund’s returns would have been lower. Updated information on the Fund’s results 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 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	Investor A Shares ANNUAL TOTAL RETURNS BlackRock International Opportunities Portfolio As of 12/31
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the ten-year period shown in the bar chart, the highest return for a quarter was 28.03% (quarter ended June 30, 2009) and the lowest return for a quarter was –24.50% (quarter ended September 30, 2008).
Bar Chart, Returns for Class Not Offered in Prospectus [Text]	rr_BarChartReturnsForClassNotOfferedInProspectus	Class R Shares do not have a performance history as of the date of this prospectus. As a result, the chart and table show you the long-term performance of International Opportunities for Investor A Shares, which are not offered in this prospectus.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	However, the table includes all applicable fees and sales charges.
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 One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown for Investor A Shares only, and the after-tax returns for Class R Shares will vary.
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. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Class R Shares will vary.
BLACKROCK INTERNATIONAL OPPORTUNITIES PORTFOLIO | Class R Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.98%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.50%
Other Expenses	rr_OtherExpensesOverAssets	0.34%	[1]
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.83%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets		[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	1.83%	[2]
1 Year	rr_ExpenseExampleYear01	186
3 Years	rr_ExpenseExampleYear03	576
BLACKROCK INTERNATIONAL OPPORTUNITIES PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
2003	rr_AnnualReturn2003	48.59%
2004	rr_AnnualReturn2004	25.53%
2005	rr_AnnualReturn2005	31.80%
2006	rr_AnnualReturn2006	31.46%
2007	rr_AnnualReturn2007	18.13%
2008	rr_AnnualReturn2008	(43.34%)
2009	rr_AnnualReturn2009	36.59%
2010	rr_AnnualReturn2010	11.42%
2011	rr_AnnualReturn2011	(14.42%)
2012	rr_AnnualReturn2012	18.02%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	28.03%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(24.50%)
1 Year	rr_AverageAnnualReturnYear01	11.83%
5 Years	rr_AverageAnnualReturnYear05	(3.77%)
10 Years	rr_AverageAnnualReturnYear10	11.98%
BLACKROCK INTERNATIONAL OPPORTUNITIES PORTFOLIO | Return After Taxes on Distributions | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	11.59%
5 Years	rr_AverageAnnualReturnYear05	(3.81%)
10 Years	rr_AverageAnnualReturnYear10	11.19%
BLACKROCK INTERNATIONAL OPPORTUNITIES PORTFOLIO | Return After Taxes on Distributions and Sale of Shares | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	8.00%
5 Years	rr_AverageAnnualReturnYear05	(3.07%)
10 Years	rr_AverageAnnualReturnYear10	10.68%
BLACKROCK INTERNATIONAL OPPORTUNITIES PORTFOLIO | MSCI All Country World Index Ex-U.S. (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.83%
5 Years	rr_AverageAnnualReturnYear05	(2.89%)
10 Years	rr_AverageAnnualReturnYear10	9.74%

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

[2] As described in the "Management of the Funds" section of the Fund's prospectus on pages 48-55, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 2.18% of average daily net assets until February 1, 2014. The Fund may have to repay some of these waivers and/or reimbursements to BlackRock in the following two years. The agreement may be terminated upon 90 days' notice by a majority of the non-interested trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund.

XML

Document and Entity Information	12 Months Ended
	Jan. 28, 2013
Risk/Return:
Document Type	Other
Document Period End Date	Sep. 30, 2012
Registrant Name	BLACKROCK FUNDS
Central Index Key	0000844779
Amendment Flag	false
Document Creation Date	Feb. 04, 2013
Document Effective Date	Feb. 04, 2013
Prospectus Date	Jan. 28, 2013

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jan. 28, 2013
BLACKROCK GLOBAL OPPORTUNITIES PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Global Opportunities Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Global Opportunities Portfolio (“Global Opportunities” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to provide long-term capital appreciation.
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 Service Shares of Global Opportunities.
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	February 1, 2014
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 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 122% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	122.00%
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	Under normal conditions, Global Opportunities will invest at least 75% of its total assets in global equity securities of any market capitalization, selected for their above-average return potential. The Fund seeks to buy primarily common stock but may also invest in preferred stock and convertible securities. The Fund may invest up to 25% of its total assets in stocks of issuers in emerging market countries. The Fund may invest up to 25% of its total assets in global fixed income securities, including corporate bonds, U.S. government debt securities, non-U.S. government and supranational debt securities, asset-backed securities, mortgage-backed securities, emerging market debt securities and non-investment grade debt securities (high yield or junk bonds). Investment in fixed income securities will be made on an opportunistic basis. Securities will be identified based on factors such as relative value and earnings estimate revisions. From time to time, the Fund may invest in shares of companies through initial public offerings (“IPOs”). The Fund will invest in securities of non-U.S. issuers that can be U.S.-dollar based or non-U.S.-dollar based on a hedged or unhedged basis. The Fund may enter into currency transactions on a hedged or unhedged basis in order to seek total return. The Fund may, when consistent with the Fund’s investment objective, buy or sell options or futures on a security or an index of securities and may buy options on a currency or a basket of currencies, or enter into foreign currency transactions, including swaps (collectively, commonly known as derivatives). The Fund typically uses derivatives as a substitute for taking a position in the underlying asset and/or as part of a strategy designed to reduce exposure to other risks, such as currency risk. The Fund may also use derivatives to enhance returns, in which case their use would involve leveraging risk. The Fund may seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as reverse repurchase agreements or dollar rolls). The Fund may also use forward foreign currency exchange contracts (obligations to buy or sell a currency at a set rate in the future).
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 Global Opportunities, 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. 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. Debt Securities Risk — Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. 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. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities. Derivatives Risk — The Fund’s use of derivatives may reduce the Fund’s returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. 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. Derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation is not yet known and may not be known for some time. New regulation may make derivatives more costly, may limit the availability of derivatives, or may otherwise adversely affect the value or performance of derivatives. 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, including countries that do not use the Euro. These events may affect the value and liquidity of certain of the Fund’s investments. Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion. Therefore, this investment style may over time go in and out of favor. At times when the investment style used by the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles. 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. “New Issues” Risk — “New Issues” are initial public offerings of equity securities of U.S. and non-U.S. issuers. Securities issued in IPOs have no trading history, and information about the companies may be available for very limited periods. In addition, the prices of securities sold in IPOs may be highly volatile or may decline shortly after the initial public offering. Small Cap Securities Risk — Small cap 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.
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	Service Shares do not have a performance history as of the date of this prospectus. As a result, the chart and table show you the long-term performance of Global Opportunities for Investor A Shares, which are not offered in this prospectus. Investor A Shares would have annual returns substantially similar to Service Shares differing only to the extent that Investor A and Service Shares have different expenses. 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. The table compares the average annual total returns of each class of the Fund’s shares with that of the MSCI All Country World Index. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If BlackRock 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 results 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 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	Investor A Shares ANNUAL TOTAL RETURNS BlackRock Global Opportunities Portfolio As of 12/31
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 24.03% (quarter ended June 30, 2009) and the lowest return for a quarter was –21.57% (quarter ended December 31, 2008).
Bar Chart, Returns for Class Not Offered in Prospectus [Text]	rr_BarChartReturnsForClassNotOfferedInProspectus	Service Shares do not have a performance history as of the date of this prospectus. As a result, the chart and table show you the long-term performance of Global Opportunities for Investor A Shares, which are not offered in this prospectus.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	However, the table includes all applicable fees and sales charges.
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 One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown for Investor A Shares only, and the after-tax returns for Service Shares will vary.
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. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Service Shares will vary.
BLACKROCK GLOBAL OPPORTUNITIES PORTFOLIO | Service Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.90%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.37%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.52%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets		[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	1.52%	[2]
1 Year	rr_ExpenseExampleYear01	155
3 Years	rr_ExpenseExampleYear03	480
BLACKROCK GLOBAL OPPORTUNITIES PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
2007	rr_AnnualReturn2007	21.09%
2008	rr_AnnualReturn2008	(38.79%)
2009	rr_AnnualReturn2009	34.50%
2010	rr_AnnualReturn2010	10.60%
2011	rr_AnnualReturn2011	(12.43%)
2012	rr_AnnualReturn2012	14.53%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	24.03%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(21.57%)
1 Year	rr_AverageAnnualReturnYear01	8.54%
5 Years	rr_AverageAnnualReturnYear05	(2.85%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.22%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 31, 2006
BLACKROCK GLOBAL OPPORTUNITIES PORTFOLIO | Return After Taxes on Distributions | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	8.38%
5 Years	rr_AverageAnnualReturnYear05	(2.91%)
Since Inception	rr_AverageAnnualReturnSinceInception	1.95%
BLACKROCK GLOBAL OPPORTUNITIES PORTFOLIO | Return After Taxes on Distributions and Sale of Shares | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	5.77%
5 Years	rr_AverageAnnualReturnYear05	(2.39%)
Since Inception	rr_AverageAnnualReturnSinceInception	1.82%
BLACKROCK GLOBAL OPPORTUNITIES PORTFOLIO | MSCI All Country World Index (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.13%
5 Years	rr_AverageAnnualReturnYear05	(1.16%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.85%

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

[2] As described in the "Management of the Funds" section of the Fund's prospectus on pages 31-36, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and/or certain other Fund expenses) to 1.70% of average daily net assets until February 1, 2014. The Fund may have to repay some of these waivers and reimbursements to BlackRock in the following two years. The contractual agreement may be terminated upon 90 days' notice by a majority of the non-interested trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jan. 28, 2013
BLACKROCK MANAGED VOLATILITY PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Managed Volatility Portfolio, formerly BlackRock Asset Allocation Portfolio (“Managed Volatility Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek total return.
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 R Shares of Managed Volatility Portfolio.
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	February 1, 2014
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 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 324% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	324.00%
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	Miscellaneous 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	Managed Volatility Portfolio uses an asset allocation strategy, investing varying percentages of its portfolio in three major categories: stocks, bonds and money market instruments. The Fund has wide flexibility in the relative weightings given to each category. The Fund may also invest a significant portion of its assets in affiliated and unaffiliated ETFs and mutual funds. See “Information About the ETFs and Mutual Funds.” With respect to its equity investments, the Fund may invest in ETFs, mutual funds or individual equity securities to an unlimited extent. The Fund, the ETFs and the mutual funds may invest in common stock, preferred stock, securities convertible into common stock, non-convertible preferred stock and depositary receipts. The Fund, the ETFs and the mutual funds may invest in securities of both U.S. and non-U.S. issuers without limit, which can be U.S. dollar-based or non-U.S. dollar-based and may be currency hedged or unhedged. The Fund, the ETFs and the mutual funds may invest in securities of companies of any market capitalization. With respect to its fixed-income investments, the Fund may invest in ETFs, mutual funds or individual fixed-income securities to an unlimited extent. The Fund, the ETFs and the mutual funds may invest in a portfolio of fixed-income securities such as corporate bonds and notes, commercial and residential mortgage-backed securities (bonds that are backed by a mortgage loan or pools of loans secured either by commercial property or residential mortgages, as applicable), collateralized mortgage obligations (bonds that are backed by cash flows from pools of mortgages and may have multiple classes with different payment rights and protections), collateralized debt obligations, asset-backed securities, convertible securities, debt obligations of governments and their sub-divisions (including those of non-U.S. governments), other floating or variable rate obligations, municipal obligations and zero coupon debt securities. The Fund, the ETFs and the mutual funds may also invest a significant portion of their assets in non-investment grade bonds (junk bonds or distressed securities), non-investment grade bank loans, foreign bonds (both U.S. dollar- and non-U.S. dollar-denominated) and bonds of emerging market issuers. The Fund, the ETFs and the mutual funds may invest in non-U.S. dollar-denominated bonds on a currency hedged or unhedged basis. With respect to its cash investments, the Fund may hold high quality money market securities, including short term U.S. Government securities, U.S. Government agency securities, securities issued by U.S. Government-sponsored enterprises and U.S. Government instrumentalities, bank obligations, commercial paper, including asset-backed commercial paper, corporate notes and repurchase agreements. The Fund may invest a significant portion of its assets in money market funds, including those advised by BlackRock or its affiliates. The Fund may invest in derivatives, including, but not limited to, interest rate, total return and credit default swaps, indexed and inverse floating rate securities, options, futures, options on futures and swaps and foreign currency transactions (including swaps), for hedging purposes, as well as to increase the return on its portfolio investments. The Fund may seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as reverse repurchase agreements or dollar rolls). The Fund may also use forward foreign currency exchange contracts (obligations to buy or sell a currency at a set rate in the future) to hedge against movement in the value of non-U.S. currencies. The ETFs and the mutual funds may, to varying degrees, also invest in derivatives. The Fund may invest in U.S. and non-U.S. real estate investment trusts (“REITs”), structured products (including, but not limited to, structured notes, credit linked notes and participation notes, or other instruments evidencing interests in special purpose vehicles, trusts, or other entities that hold or represent interests in fixed-income securities) and floating rate securities (such as bank loans). The Fund incorporates a volatility control process that seeks to reduce risk when portfolio volatility is expected to deviate from the Fund’s targeted total return volatility of 10% over a one-year period. Volatility is a statistical measurement of the magnitude of up and down fluctuations in the value of a financial instrument or index over time. Volatility may result in rapid and dramatic price swings. While BlackRock attempts to manage the Fund’s volatility exposure to stabilize performance, there can be no guarantee that the Fund will reach its target volatility. The Fund will adjust its asset allocation in response to periods of high or low expected volatility. The Fund may without limitation allocate assets into cash or short-term fixed-income securities, and away from riskier assets such as equity and high yield fixed-income securities. When volatility decreases, the Fund may move assets out of cash and back into riskier securities. At any given time, the Fund may be invested entirely in equities, fixed-income or cash. As part of its attempt to manage the Fund’s volatility exposure, during certain periods the Fund may make significant investments in index futures or other derivative instruments designed to reduce the Fund’s exposure to portfolio volatility. The Fund may engage in active and frequent trading of portfolio securities to achieve its primary investment strategies.
Risk [Heading]	rr_RiskHeading	Investment Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	Risk is inherent in all investing. The value of your investment in Managed Volatility Portfolio, 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 principal risks set forth below are the principal risks of investing in the Fund and/or the ETFs and the mutual funds (each, an “Underlying Fund”). Principal Risks of the Fund’s Fund of Funds Structure Affiliated Fund Risk — In managing the Fund, BlackRock will have authority to select and substitute ETFs or mutual funds. BlackRock may be subject to potential conflicts of interest in selecting ETFs or mutual funds because the fees paid to BlackRock by some ETFs or mutual funds are higher than the fees paid by other ETFs or mutual funds. However, BlackRock is a fiduciary to the Fund and is legally obligated to act in the Fund’s best interests when selecting ETFs and mutual funds. Allocation Risk — The Fund’s ability to achieve its investment objective depends upon BlackRock’s skill in determining the Fund’s strategic asset class allocation and in selecting the best mix of ETFs, mutual funds and direct investments. There is a risk that BlackRock’s evaluations and assumptions regarding asset classes or ETFs or mutual funds may be incorrect in view of actual market conditions. Investments in ETFs and Other Mutual Funds Risk — The Fund’s net asset value will change with changes in the value of the ETFs, mutual funds and other securities in which it invests. As with other investments, investments in other investment companies, including ETFs, are subject to market risk and, for non-index strategies, selection risk. In addition, if the Fund acquires shares of investment companies, including ETFs, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies. If the Fund acquires shares of affiliated mutual funds, shareholders bear both their proportionate share of expenses in the Fund (excluding management and advisory fees) and, indirectly, the expenses of the mutual funds. To the extent the Fund is held by an affiliated fund, the ability of the Fund itself to hold other investment companies may be limited. One ETF or mutual fund may buy the same securities that another ETF or mutual fund sells. In addition, the Fund may buy the same securities that an ETF or mutual fund sells, or vice-versa. If this happens, an investor in the Fund would indirectly bear the costs of these transactions without accomplishing the intended investment purpose. Also, an investor in the Fund may receive taxable gains from portfolio transactions by an ETF or mutual fund, as well as taxable gains from transactions in shares of the ETF or mutual fund by the Fund. Certain of the ETFs or mutual funds may hold common portfolio securities, thereby reducing the diversification benefits of the Fund. Principal ETF-Specific Risks Cash Transaction Risk — Certain ETFs intend to effect creations and redemptions principally for cash, rather than primarily in-kind because of the nature of the ETF’s investments. Investments in such ETFs may be less tax efficient than investments in ETFs that effect creations and redemptions in-kind. Management Risk — If an ETF does not fully replicate the underlying index, it is subject to the risk that the manager’s investment management strategy may not produce the intended results. Passive Investment Risk — ETFs purchased by the Fund are not actively managed and may be affected by a general decline in market segments relating to their respective indices. An ETF typically invests in securities included in, or representative of, its index regardless of their investment merits and does not attempt to take defensive positions in declining markets. Representative Sampling Risk — When an ETF deviates from a full replication indexing strategy to utilize a representative sampling strategy, the ETF is subject to an increased risk of tracking error, in that the securities selected in the aggregate for the ETF may not have an investment profile similar to those of its index. Shares of an ETF May Trade at Prices Other Than Net Asset Value — The trading prices of an ETF’s shares fluctuate continuously throughout trading hours based on market supply and demand rather than net asset value. The trading prices of an ETF’s shares may deviate significantly from net asset value during periods of market volatility. Any of these factors may lead to an ETF’s shares trading at a premium or discount to net asset value. However, because shares can be created and redeemed in Creation Units, which are aggregated blocks of shares that authorized participants who have entered into agreements with the ETF’s distributor can purchase or redeem directly from the ETF, at net asset value, large discounts or premiums to the net asset value of an ETF are not likely to be sustained over the long term. If a shareholder purchases at a time when the market price is at a premium to the net asset value or sells at a time when the market price is at a discount to the net asset value, the shareholder may sustain losses. Tracking Error Risk — Imperfect correlation between an ETF’s portfolio securities and those in its index, rounding of prices, the timing of cash flows, the ETF’s size, changes to the index and regulatory requirements may cause tracking error, which is the divergence of an ETF’s performance from that of its underlying index. This risk may be heightened during times of increased market volatility or other unusual market conditions. Tracking error also may result because an ETF incurs fees and expenses while its underlying index does not. Other Principal Risks of Investing in the Fund and/or an Underlying Fund Collateralized Debt Obligations Risk — The pool of high yield securities underlying collateralized debt obligations is typically separated into groupings called tranches representing different degrees of credit quality. The higher quality tranches have greater degrees of protection and pay lower interest rates. The lower tranches, with greater risk, pay higher interest rates. Concentration Risk — To the extent that the Fund’s or an Underlying Fund’s portfolio reflects concentration in the securities of issuers in a particular region, market, industry, group of industries, country, group of countries, sector or asset class, the Fund or the Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that region, market, industry, group of industries, country, group of countries, sector or asset class. 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, wide bid/ask spreads and extended trade settlement periods. The corporate loans in which the Fund or an Underlying Fund invests are usually rated below investment grade. Counterparty Risk — The counterparty to an over-the-counter derivatives contract or a borrower of the Fund’s or an Underlying Fund’s securities may be unable or unwilling to make timely principal, interest or settlement payments, or otherwise to honor its obligations. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. The degree of credit risk depends on the issuer’s financial condition and on the terms of the securities. Debt Securities Risk — Debt securities, such as bonds, involve credit risk. Debt securities are also subject to interest rate risk. Derivatives Risk — The Fund’s or an Underlying Fund’s use of derivatives may reduce the Fund’s or the Underlying Fund’s returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s or an Underlying Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or an Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or the Underlying Fund to losses and could make derivatives more difficult for the Fund or the Underlying Fund to value accurately. Derivatives may give rise to a form of leverage and may expose the Fund or an Underlying Fund to greater risk and increase its costs. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation is not yet known and may not be known for some time. New regulation may make derivatives more costly, may limit the availability of derivatives, or may otherwise adversely affect the value or performance of derivatives. Distressed Securities Risk — Distressed securities are speculative and involve substantial risks in addition to the risks of investing in junk bonds. The Fund and the Underlying Funds 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. Dollar Rolls Risk — Dollar rolls involve the risk that the market value of the securities that the Fund or an Underlying Fund is committed to buy may decline below the price of the securities the Fund or the Underlying Fund has sold. These transactions may involve leverage. 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. Extension Risk — When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall. Foreign Securities Risk — Foreign investments often involve special risks not present in U.S. investments that can increase the chances that the Fund or an Underlying Fund will lose money. These risks include: — The Fund and the Underlying Funds generally hold their 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 or an Underlying 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, including countries that do not use the Euro. These events may affect the value and liquidity of certain of the Fund’s or an Underlying Fund’s investments. High Portfolio Turnover Risk — High portfolio turnover (more than 100%) may result in increased transaction costs to the Fund or an Underlying Fund and potentially higher capital gains or losses for shareholders. The effects of higher than normal portfolio turnover may adversely affect Fund or Underlying Fund performance. Indexed and Inverse Securities Risk — Certain indexed and inverse securities have greater sensitivity to changes in interest rates or index levels than other securities, and the Fund’s or an Underlying Fund’s investment in such instruments may decline significantly in value if interest rates or index levels move in a way Fund or Underlying Fund management does not anticipate. Inflation Indexed Bonds Risk — The principal value of an investment is not protected or otherwise guaranteed by virtue of the Fund’s or an Underlying Fund’s investments in inflation-indexed bonds. Inflation-indexed bonds are fixed-income securities whose principal value is periodically adjusted according to the rate of inflation. If the index measuring inflation falls, the principal value of inflation-indexed bonds will be adjusted downward, and consequently the interest payable on these securities (calculated with respect to a smaller principal amount) will be reduced. Repayment of the original bond principal upon maturity (as adjusted for inflation) is guaranteed in the case of U.S. Treasury inflation-indexed bonds. For bonds that do not provide a similar guarantee, the adjusted principal value of the bond repaid at maturity may be less than the original principal value. The value of inflation-indexed bonds is expected to change in response to changes in real interest rates. Real interest rates are tied to the relationship between nominal interest rates and the rate of inflation. If nominal interest rates increase at a faster rate than inflation, real interest rates may rise, leading to a decrease in value of inflation-indexed bonds. Short-term increases in inflation may lead to a decline in value. Any increase in the principal amount of an inflation-indexed bond will be considered taxable ordinary income, even though investors do not receive their principal until maturity. Periodic adjustments for inflation to the principal amount of an inflation-indexed bond may give rise to original issue discount, which will be includable in the Fund’s or an Underlying Fund’s gross income. Due to original issue discount, the Fund or an Underlying Fund may be required to make annual distributions to shareholders that exceed the cash received, which may cause the Fund or the Underlying Fund to liquidate certain investments when it is not advantageous to do so. Also, if the principal value of an inflation-indexed bond is adjusted downward due to deflation, amounts previously distributed in the taxable year may be characterized in some circumstances as a return of capital. Interest Rate Risk — 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. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities. Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion and value investments have performed better during periods of economic recovery. Therefore, these investment styles may over time go in and out of favor. At times when the investment style used by the Fund or Underlying Fund is out of favor, the Fund or Underlying Fund may underperform other funds that use different investment styles. 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 or Underlying 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 or an Underlying Fund to greater risk and increase its costs. The use of leverage may cause the Fund or an Underlying 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 or an Underlying Fund’s portfolio will be magnified when the Fund or the Underlying Fund uses leverage. Liquidity Risk — Liquidity risk exists when particular investments are difficult to purchase or sell. The Fund’s or an Underlying Fund’s investments in illiquid securities may reduce the returns of the Fund or the Underlying Fund because it may be difficult to sell the illiquid securities at an advantageous time or price. To the extent that the Fund’s or an Underlying Fund’s principal investment strategies involve derivatives or securities with substantial market and/or credit risk, the Fund will tend to have the greatest exposure to liquidity risk. Liquid investments may become illiquid after purchase by the Fund or an Underlying Fund, particularly during periods of market turmoil. Illiquid investments may be harder to value, especially in changing markets, and if the Fund or the Underlying Fund is forced to sell these investments to meet redemption requests or for other cash needs, the Fund or the Underlying Fund may suffer a loss. In addition, when there is illiquidity in the market for certain securities, the Fund or an Underlying Fund, due to limitations on illiquid investments, may be subject to purchase and sale restrictions. Market Risk and Selection Risk — Market risk is the risk that one or more markets in which the Fund or an Underlying 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 or Underlying 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. Municipal Securities Risks — Municipal securities risks include the ability of the issuer to repay the obligation, the relative lack of information about certain issuers of municipal securities, and the possibility of future legislative changes which could affect the market for and value of municipal securities. These risks include: General Obligation Bonds Risks — Timely payments depend on the issuer’s credit quality, ability to raise tax revenues and ability to maintain an adequate tax base. Revenue Bonds Risks — These payments depend on the money earned by the particular facility or class of facilities, or the amount of revenues derived from another source. Private Activity Bonds Risks — Municipalities and other public authorities issue private activity bonds to finance development of industrial facilities for use by a private enterprise. The private enterprise pays the principal and interest on the bond, and the issuer does not pledge its faith, credit and taxing power for repayment. Moral Obligation Bonds Risks — Moral obligation bonds are generally issued by special purpose public authorities of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral commitment, but not a legal obligation, of the state or municipality. Municipal Notes Risks — Municipal notes are shorter term municipal debt obligations. If there is a shortfall in the anticipated proceeds, the notes may not be fully repaid and the Fund or an Underlying Fund may lose money. Municipal Lease Obligations Risks — In a municipal lease obligation, the issuer agrees to make payments when due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease obligation, the lease obligation is secured by the leased property. Preferred Securities Risk — Preferred securities may pay fixed or adjustable rates of return. Preferred securities are subject to issuer-specific and market risks applicable generally to equity securities. Prepayment Risk — When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund or an Underlying Fund may have to invest the proceeds in securities with lower yields. Real Estate Related Securities Risks — 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 or an Underlying Fund’s real estate related investments are concentrated in one geographic area or in one property type, the Fund or the Underlying 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. Repurchase Agreements and Purchase and Sale Contracts Risks — If the other party to a repurchase agreement or purchase and sale contract defaults on its obligation under the agreement, the Fund or an Underlying Fund may suffer delays and incur costs or lose money in exercising its rights under the agreement. If the seller fails to repurchase the security in either situation and the market value of the security declines, the Fund or an Underlying Fund may lose money. Reverse Repurchase Agreements Risk — Reverse repurchase agreements involve the risk that the other party to the reverse repurchase agreement may fail to return the securities in a timely manner or at all. The Fund or an Underlying Fund could lose money if it is unable to recover the securities and the value of the collateral held by the Fund or the Underlying Fund, including the value of the investments made with cash collateral, is less than the value of securities. These events could also trigger adverse tax consequences to the Fund or an Underlying Fund. Risks of Loan Assignments and Participations — As the purchaser of an assignment, the Fund or an Underlying Fund typically succeeds to all the rights and obligations of the assigning institution and becomes a lender under the credit agreement with respect to the debt obligation; however, the Fund or an Underlying Fund may not be able unilaterally to enforce all rights and remedies under the loan and with regard to any associated collateral. Because assignments may be arranged through private negotiations between potential assignees and potential assignors, the rights and obligations acquired by the Fund or an Underlying Fund as the purchaser of an assignment may differ from, and be more limited than, those held by the assigning lender. In addition, if the loan is foreclosed, the Fund or an Underlying Fund could become part owner of any collateral and could bear the costs and liabilities of owning and disposing of the collateral. The Fund or an Underlying Fund may be required to pass along to a purchaser that buys a loan from the Fund or the Underlying Fund by way of assignment a portion of any fees to which the Fund or the Underlying Fund is entitled under the loan. In connection with purchasing participations, the Fund or an Underlying Fund generally will have no right to enforce compliance by the borrower with the terms of the loan agreement relating to the loan, nor any rights of set-off against the borrower, and the Fund or an Underlying Fund may not directly benefit from any collateral supporting the loan in which it has purchased the participation. As a result, the Fund or an Underlying Fund will be subject to the credit risk of both the borrower and the lender that is selling the participation. In the event of the insolvency of the lender selling a participation, the Fund or an Underlying Fund may be treated as a general creditor of the lender and may not benefit from any set-off between the lender and the borrower. Second Lien Loans Risk — Second lien loans generally are subject to similar risks as those associated with investments in senior loans. Because second lien loans are subordinated or unsecured and thus lower in priority of payment to senior loans, they are subject to the additional risk that the cash flow of the borrower and property securing the loan or debt, if any, may be insufficient to meet scheduled payments after giving effect to the senior secured obligations of the borrower. Senior Loans Risk —There is less readily available, reliable information about most senior loans than is the case for many other types of securities. An economic downturn generally leads to a higher non-payment rate, and a senior loan may lose significant value before a default occurs. Moreover, any specific collateral used to secure a senior loan may decline in value or become illiquid, which would adversely affect the senior loan’s value. No active trading market may exist for certain senior loans, which may impair the ability of the Fund or an Underlying Fund to realize full value in the event of the need to sell a senior loan and which may make it difficult to value senior loans. Although senior loans in which the Fund or an Underlying Fund will invest generally will be secured by specific collateral, there can be no assurance that liquidation of such collateral would satisfy the borrower’s obligation in the event of non-payment of scheduled interest or principal or that such collateral could be readily liquidated. To the extent that a senior loan is collateralized by stock in the borrower or its subsidiaries, such stock may lose all of its value in the event of the bankruptcy of the borrower. Uncollateralized senior loans involve a greater risk of loss. The senior loans in which the Fund or an Underlying Fund invests are usually rated below investment grade. Small Cap and Emerging Growth Securities Risks — 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 or an Underlying 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 or an Underlying 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. Structured Products Risk — Holders of structured products bear risks of the underlying investments, index or reference obligation and are subject to counterparty risk. The Fund or an Underlying Fund may have the right to receive payments only from the structured product, and generally does not have direct rights against the issuer or the entity that sold the assets to be securitized. Certain structured products may be thinly traded or have a limited trading market. In addition to the general risks associated with debt securities discussed herein, structured products carry additional risks, including, but not limited to: the possibility that distributions from collateral securities will not be adequate to make interest or other payments; the quality of the collateral may decline in value or default; and the possibility that the structured products are subordinate to other classes. Supranational Entities Risk — The Fund or an Underlying Fund may invest in obligations issued or guaranteed by the International Bank for Reconstruction and Development (the World Bank). If one or more stockholders of the World Bank fail to make necessary additional capital contributions, the entity may be unable to pay interest or repay principal on its debt securities, and the Fund or an Underlying Fund may lose money on such investments. Tender Option Bonds and Related Securities Risk — Investments in tender option bonds, residual interest tender option bonds and inverse floaters expose the Fund or an Underlying Fund to the same risks as investments in derivatives, as well as risks associated with leverage, described above, especially the risk of increased volatility. An investment in these securities may be subject to the risk of loss of principal. Residual interest tender option bonds and inverse floaters generally will underperform the market for fixed rate municipal securities in a rising interest rate environment. U.S. Government Mortgage-Related Securities Risk — There are a number of important differences among the agencies and instrumentalities of the U.S. Government that issue mortgage-related securities and among the securities that they issue. Mortgage-related securities guaranteed by the Government National Mortgage Association (“Ginnie Mae”) are guaranteed as to the timely payment of principal and interest by Ginnie Mae and such guarantee is backed by the full faith and credit of the United States. Ginnie Mae securities also are supported by the right of Ginnie Mae to borrow funds from the U.S. Treasury to make payments under its guarantee. Mortgage-related securities issued by The Federal National Mortgage Association (“Fannie Mae”) or The Federal Home Loan Mortgage Corporation (“Freddie Mac”) are solely the obligations of Fannie Mae or Freddie Mac, as the case may be, and are not backed by or entitled to the full faith and credit of the United States but are supported by the right of the issuer to borrow from the U.S. Treasury. U.S. Government Obligations Risk — Certain securities in which the Fund or an Underlying Fund may invest, including securities issued by certain U.S. Government agencies and U.S. Government sponsored enterprises, are not guaranteed by the U.S. Government or supported by the full faith and credit of the United States. Variable and Floating Rate Instrument Risk — The absence of an active market for these securities could make it difficult for the Fund or an Underlying Fund to dispose of them if the issuer defaults. 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 or an Underlying Fund loses any amount it paid for the warrant. Thus, investments in warrants may involve substantially more risk than investments in common stock. Zero Coupon Securities Risk — While interest payments are not made on such securities, holders of such securities are deemed to have received income (“phantom income”) annually, notwithstanding that cash may not be received currently. Some of these securities may be subject to substantially greater price fluctuations during periods of changing market interest rates than are comparable securities that pay interest currently. Longer term zero coupon bonds are more exposed to interest rate risk than shorter term zero coupon bonds.
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	Class R Shares do not have a performance history as of the date of this prospectus. As a result, the chart and table show you the long-term performance of Managed Volatility Portfolio for Investor A Shares, which are not offered in this prospectus. Investor A Shares would have annual returns substantially similar to Class R Shares differing only to the extent that Investor A and Class R Shares have different expenses. The actual return of Class R Shares would generally be lower than that of Investor A Shares because Class R Shares are subject to higher distribution and/or service (12b-1) fees than Investor A Shares. Effective May 15, 2012, the Fund changed its investment strategy to invest a significant portion of its assets in ETFs and, to a lesser extent, in mutual funds and directly in securities. Performance for the periods prior to May 15, 2012 shown below is based on the investment strategy utilized by the Fund, which focused on investing directly in securities. On January 31, 2005, the Fund reorganized with the State Street Research Asset Allocation Fund (the “SSR Fund”), which had investment objectives and strategies similar to the Fund. For periods prior to January 31, 2005, the chart and table show performance information for the SSR Fund. 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. The table compares the Fund’s performance to that of the MSCI All Country World Index (the “MSCI ACWI Index”), the Citigroup World Government Bond Index (hedged into USD) (the “Citigroup WGBI (hedged into USD)”), the Barclays U.S. Aggregate Bond Index and two customized weighted indices comprised of the returns of the MSCI ACWI Index, the Citigroup WGBI (hedged into USD) and the Barclays U.S. Aggregate Bond Index in the percentages and combinations set forth in the table. Effective May 15, 2012, the Fund changed one of the components making up the customized weighted index from the Barclays U.S. Aggregate Bond Index to the Citigroup WGBI (hedged into USD). Fund management believes that the Citigroup WGBI (hedged into USD) better reflects the Fund’s increasing global exposure. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If BlackRock 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 results 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 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	Investor A Shares ANNUAL TOTAL RETURNS BlackRock Managed Volatility Portfolio As of 12/31
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the ten-year period shown in the bar chart, the highest return for a quarter was 13.66% (quarter ended September 30, 2009) and the lowest return for a quarter was –13.17% (quarter ended December 31, 2008).
Bar Chart, Returns for Class Not Offered in Prospectus [Text]	rr_BarChartReturnsForClassNotOfferedInProspectus	Class R Shares do not have a performance history as of the date of this prospectus. As a result, the chart and table show you the long-term performance of Managed Volatility Portfolio for Investor A Shares, which are not offered in this prospectus.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	However, the table includes all applicable fees and sales charges.
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 One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown for Investor A Shares only, and the after-tax returns for Class R Shares will vary.
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. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Class R Shares will vary.
BLACKROCK MANAGED VOLATILITY PORTFOLIO | Class R Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.55%	[1]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.50%
Interest Expense	rr_Component1OtherExpensesOverAssets	0.01%
Miscellaneous Other Expenses	rr_Component2OtherExpensesOverAssets	0.42%	[2]
Other Expenses	rr_OtherExpensesOverAssets	0.43%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.05%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.53%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets		[3]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	1.53%	[3]
1 Year	rr_ExpenseExampleYear01	156
3 Years	rr_ExpenseExampleYear03	483
BLACKROCK MANAGED VOLATILITY PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
2003	rr_AnnualReturn2003	25.77%
2004	rr_AnnualReturn2004	11.50%
2005	rr_AnnualReturn2005	6.46%
2006	rr_AnnualReturn2006	10.39%
2007	rr_AnnualReturn2007	9.68%
2008	rr_AnnualReturn2008	(26.90%)
2009	rr_AnnualReturn2009	26.43%	[4]
2010	rr_AnnualReturn2010	13.74%
2011	rr_AnnualReturn2011	(3.52%)
2012	rr_AnnualReturn2012	11.97%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	13.66%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(13.17%)
1 Year	rr_AverageAnnualReturnYear01	6.12%
5 Years	rr_AverageAnnualReturnYear05	1.47%	[4]
10 Years	rr_AverageAnnualReturnYear10	6.69%	[4]
BLACKROCK MANAGED VOLATILITY PORTFOLIO | Return After Taxes on Distributions | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	4.80%
5 Years	rr_AverageAnnualReturnYear05	0.84%	[4]
10 Years	rr_AverageAnnualReturnYear10	5.75%	[4]
BLACKROCK MANAGED VOLATILITY PORTFOLIO | Return After Taxes on Distributions and Sale of Shares | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	4.65%
5 Years	rr_AverageAnnualReturnYear05	1.05%	[4]
10 Years	rr_AverageAnnualReturnYear10	5.54%	[4]
BLACKROCK MANAGED VOLATILITY PORTFOLIO | MSCI ACWI Index (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.13%
5 Years	rr_AverageAnnualReturnYear05	(1.16%)	[4]
10 Years	rr_AverageAnnualReturnYear10	8.11%	[4]
BLACKROCK MANAGED VOLATILITY PORTFOLIO | Citigroup WGBI (hedged into USD) (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	4.50%
5 Years	rr_AverageAnnualReturnYear05	4.68%	[4]
10 Years	rr_AverageAnnualReturnYear10	4.41%	[4]
BLACKROCK MANAGED VOLATILITY PORTFOLIO | 60% MSCI ACWI Index/40% Citigroup WGBI (hedged into USD) (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	11.61%
5 Years	rr_AverageAnnualReturnYear05	1.79%	[4]
10 Years	rr_AverageAnnualReturnYear10	7.03%	[4]
BLACKROCK MANAGED VOLATILITY PORTFOLIO | Barclays U.S. Aggregate Bond Index (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	4.21%
5 Years	rr_AverageAnnualReturnYear05	5.95%	[4]
10 Years	rr_AverageAnnualReturnYear10	5.18%	[4]
BLACKROCK MANAGED VOLATILITY PORTFOLIO | 60% MSCI ACWI Index/40% Barclays U.S. Aggregate Bond Index (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	11.48%
5 Years	rr_AverageAnnualReturnYear05	2.20%	[4]
10 Years	rr_AverageAnnualReturnYear10	7.30%	[4]

[1] The Management Fee payable by the Fund is based on assets estimated to be attributable to the Fund's direct investments in fixed-income and equity securities and instruments, including exchange-traded funds ("ETFs") advised by BlackRock or other investment advisers, other investments and cash and cash equivalents (including money market funds). BlackRock has contractually agreed to waive the Management Fee on assets estimated to be attributed to the Fund's investments in other equity and fixed-income mutual funds managed by BlackRock or its affiliates (the "mutual funds").

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

[3] As described in the "Management of the Fund" section of the Fund's prospectus on pages 76-80, BlackRock has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 1.81% of average daily net assets until February 1, 2014. The Fund may have to repay some of these waivers and/or reimbursements to BlackRock in the following two years. The agreement may be terminated upon 90 days' notice by a majority of the non-interested Trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund.

[4] A portion of the Fund's total return was attributable to proceeds received in the fiscal year ended September 30, 2009 in settlement of litigation.

XML

BLACKROCK GLOBAL OPPORTUNITIES PORTFOLIO

Fund Overview

Key Facts About BlackRock Global Opportunities Portfolio

Investment Objective

The investment objective of BlackRock Global Opportunities Portfolio (“Global Opportunities” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to provide long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold Service Shares of Global Opportunities.

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses		BLACKROCK GLOBAL OPPORTUNITIES PORTFOLIO Service Shares
Management Fee		0.90%
Distribution and/or Service (12b-1) Fees		0.25%
Other Expenses	[1]	0.37%
Total Annual Fund Operating Expenses		1.52%
Fee Waivers and/or Expense Reimbursements	[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[2]	1.52%

Example:

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:

Expense Example (USD $)	1 Year	3 Years
BLACKROCK GLOBAL OPPORTUNITIES PORTFOLIO Service Shares	155	480

Portfolio Turnover:

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover 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 122% of the average value of its portfolio.

Principal Investment Strategies of the Fund

Under normal conditions, Global Opportunities will invest at least 75% of its total assets in global equity securities of any market capitalization, selected for their above-average return potential. The Fund seeks to buy primarily common stock but may also invest in preferred stock and convertible securities. The Fund may invest up to 25% of its total assets in stocks of issuers in emerging market countries.

The Fund may invest up to 25% of its total assets in global fixed income securities, including corporate bonds, U.S. government debt securities, non-U.S. government and supranational debt securities, asset-backed securities, mortgage-backed securities, emerging market debt securities and non-investment grade debt securities (high yield or junk bonds). Investment in fixed income securities will be made on an opportunistic basis. Securities will be identified based on factors such as relative value and earnings estimate revisions.

From time to time, the Fund may invest in shares of companies through initial public offerings (“IPOs”). The Fund will invest in securities of non-U.S. issuers that can be U.S.-dollar based or non-U.S.-dollar based on a hedged or unhedged basis. The Fund may enter into currency transactions on a hedged or unhedged basis in order to seek total return.

The Fund may, when consistent with the Fund’s investment objective, buy or sell options or futures on a security or an index of securities and may buy options on a currency or a basket of currencies, or enter into foreign currency transactions, including swaps (collectively, commonly known as derivatives). The Fund typically uses derivatives as a substitute for taking a position in the underlying asset and/or as part of a strategy designed to reduce exposure to other risks, such as currency risk. The Fund may also use derivatives to enhance returns, in which case their use would involve leveraging risk. The Fund may seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as reverse repurchase agreements or dollar rolls). The Fund may also use forward foreign currency exchange contracts (obligations to buy or sell a currency at a set rate in the future).

Principal Risks of Investing in the Fund

Risk is inherent in all investing. The value of your investment in Global Opportunities, 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.

• 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.

• Debt Securities Risk — Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. 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. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

• Derivatives Risk — The Fund’s use of derivatives may reduce the Fund’s returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. 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. Derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation is not yet known and may not be known for some time. New regulation may make derivatives more costly, may limit the availability of derivatives, or may otherwise adversely affect the value or performance of derivatives.

• 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, including countries that do not use the Euro. These events may affect the value and liquidity of certain of the Fund’s investments.

• Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion. Therefore, this investment style may over time go in and out of favor. At times when the investment style used by the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.

• 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.

• “New Issues” Risk — “New Issues” are initial public offerings of equity securities of U.S. and non-U.S. issuers. Securities issued in IPOs have no trading history, and information about the companies may be available for very limited periods. In addition, the prices of securities sold in IPOs may be highly volatile or may decline shortly after the initial public offering.

• Small Cap Securities Risk — Small cap 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.

Performance Information

Service Shares do not have a performance history as of the date of this prospectus. As a result, the chart and table show you the long-term performance of Global Opportunities for Investor A Shares, which are not offered in this prospectus. Investor A Shares would have annual returns substantially similar to Service Shares differing only to the extent that Investor A and Service Shares have different expenses.

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. The table compares the average annual total returns of each class of the Fund’s shares with that of the MSCI All Country World Index. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If BlackRock 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 results can be obtained by visiting http://www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Investor A Shares
ANNUAL TOTAL RETURNS
BlackRock Global Opportunities Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 24.03% (quarter ended June 30, 2009) and the lowest return for a quarter was –21.57% (quarter ended December 31, 2008).

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns BLACKROCK GLOBAL OPPORTUNITIES PORTFOLIO	1 Year	5 Years	Since Inception	Inception Date
Investor A	8.54%	(2.85%)	2.22%	Jan. 31, 2006
Investor A Return After Taxes on Distributions	8.38%	(2.91%)	1.95%
Investor A Return After Taxes on Distributions and Sale of Shares	5.77%	(2.39%)	1.82%
MSCI All Country World Index (Reflects no deduction for fees, expenses or taxes)	16.13%	(1.16%)	2.85%

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. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Service Shares will vary.

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

[2] As described in the "Management of the Funds" section of the Fund's prospectus on pages 31-36, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and/or certain other Fund expenses) to 1.70% of average daily net assets until February 1, 2014. The Fund may have to repay some of these waivers and reimbursements to BlackRock in the following two years. The contractual agreement may be terminated upon 90 days' notice by a majority of the non-interested trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jan. 28, 2013
Document Creation Date	dei_DocumentCreationDate	Feb. 04, 2013