485BPOS

As filed with the Securities and Exchange Commission on August 16, 2013

Securities Act File No. 33-26305

Investment Company Act File No. 811-05742

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933	x
Pre-Effective Amendment No.	¨
Post-Effective Amendment No. 307	x
and/or
REGISTRATION STATEMENT
UNDER
THE INVESTMENT COMPANY ACT OF 1940	x
Amendment No. 309	x
(Check appropriate box or boxes)

BLACKROCK FUNDS^SM

(Exact Name of Registrant as Specified in Charter)

100 Bellevue Parkway

Wilmington, Delaware 19809

(Address of Principal Executive Office)

Registrant’s Telephone Number, including Area Code (800) 441-7762

John M. Perlowski

BlackRock Funds^SM

55 East 52^nd Street

New York, New York 10055

United States of America

(Name and Address of Agent for Service)

Copies to:

Frank P. Bruno, Esq. Sidley Austin LLP 787 Seventh Avenue New York, New York 10019-6018 Benjamin Archibald, Esq. BlackRock Advisors, LLC 55 East 52^nd Street New York, New York 10055

It is proposed that this filing will become effective (check appropriate box)

x Immediately upon filing pursuant to paragraph (b)

¨ On (date) pursuant to paragraph (b)

¨ 60 days after filing pursuant to paragraph (a)(1)

¨ On (date) pursuant to paragraph (a)(1)

¨ 75 days after filing pursuant to paragraph (a)(2)

¨ On (date) pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

¨ This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

Title of Securities Being Registered: Shares of beneficial interest, par value $.001 per share.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all the requirements for effectiveness of this Post-Effective Amendment to its Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Post-Effective Amendment to its Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York, and the State of New York, on August 16, 2013.

BLACKROCK FUNDSSM,
on behalf of BlackRock Money Market Portfolio, BlackRock U.S. Treasury Money Market Portfolio, BlackRock Municipal Money Market Portfolio, BlackRock New Jersey Municipal Money Market Portfolio, BlackRock North Carolina Municipal Money Market Portfolio, BlackRock Ohio Municipal Money Market Portfolio, BlackRock Pennsylvania Municipal Money Market Portfolio and BlackRock Virginia Municipal Money Market Portfolio
(Registrant)
By:	/s/ JOHN M. PERLOWSKI
	John M. Perlowski
	President and Chief Executive Officer

Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment to its Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.

Signature	Title	Date
/S/    JOHN M. PERLOWSKI	President and Chief Executive Officer	August 16, 2013
John M. Perlowski	(Principal Executive Officer)
/S/    NEAL J. ANDREWS	Chief Financial Officer	August 16, 2013
Neal J. Andrews	(Principal Financial and Accounting Officer)
DAVID O. BEIM*	Trustee
David O. Beim
RONALD W. FORBES*	Trustee
Ronald W. Forbes
DR. MATINA S. HORNER*	Trustee
Dr. Matina S. Horner
RODNEY D. JOHNSON*	Trustee
Rodney D. Johnson
HERBERT I. LONDON*	Trustee
Herbert I. London
IAN A. MACKINNON*	Trustee
Ian A. MacKinnon
CYNTHIA A. MONTGOMERY*	Trustee
Cynthia A. Montgomery

2

JOSEPH P. PLATT*	Trustee
Joseph P. Platt
ROBERT C. ROBB, JR.*	Trustee
Robert C. Robb, Jr.
TOBY ROSENBLATT*	Trustee
Toby Rosenblatt
KENNETH L. URISH*	Trustee
Kenneth L. Urish
FREDERICK W. WINTER*	Trustee
Frederick W. Winter
PAUL L. AUDET*	Trustee
Paul L. Audet
HENRY GABBAY*	Trustee
Henry Gabbay

*By:	/S/    BENJAMIN ARCHIBALD	August 16, 2013
	Benjamin Archibald (Attorney-in-Fact)

3

EXHIBIT INDEX

Index No.	Description of Exhibit
EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-101.CAL	XBRL Taxonomy Extension Calculation Linkbase
EX-101.DEF	XBRL Taxonomy Extension Definition Linkbase
EX-101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase

4

XML

Service | BLACKROCK PA MUNI MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock Pennsylvania Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock Pennsylvania Municipal Money Market Portfolio (the “Pennsylvania Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Pennsylvania personal income tax, as is consistent with maintaining liquidity and stability of principal.

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 the Pennsylvania Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses		Service BLACKROCK PA MUNI MONEY MARKET PORTFOLIO Service Shares
Management Fee		0.45%
Service Fees		0.25%
Other Expenses		0.28%
Total Annual Fund Operating Expenses		0.98%
Fee Waivers and/or Expense Reimbursements	[1]	(0.26%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.72%

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	5 Years	10 Years
Service BLACKROCK PA MUNI MONEY MARKET PORTFOLIO Service Shares	74	286	516	1,178

Principal Investment Strategies of the Fund

The Pennsylvania Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the Commonwealth of Pennsylvania or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Pennsylvania municipal securities”). The Fund normally invests at least 80% of its net assets in Pennsylvania municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The Pennsylvania Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• State Specific Risk — The Fund will invest primarily in Pennsylvania municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Pennsylvania municipal securities.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Pennsylvania municipal securities to be subject to state or local income taxation, or the value of Pennsylvania municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the Pennsylvania Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.

Service Shares
ANNUAL TOTAL RETURNS
Pennsylvania Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.78% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns	1 Year	5 Years	10 Years
Service BLACKROCK PA MUNI MONEY MARKET PORTFOLIO Service Shares	none	0.31%	1.03%

To obtain the Fund’s current 7-day yield, call (800) 537-4942.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.72% of average daily net assets until August 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 Pennsylvania Municipal Money Market Portfolio.

XML

Service | BLACKROCK VA MUNI MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock Virginia Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock Virginia Municipal Money Market Portfolio (the “Virginia Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Virginia state income tax, as is consistent with maintaining liquidity and stability of principal.

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 the Virginia Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses		Service BLACKROCK VA MUNI MONEY MARKET PORTFOLIO Service Shares
Management Fee	[1]	0.45%
Service Fees	[1]	0.25%
Other Expenses	[1]	0.49%
Total Annual Fund Operating Expenses	[1]	1.19%
Fee Waivers and/or Expense Reimbursements	[1][2]	(0.59%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1][2]	0.60%

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	5 Years	10 Years
Service BLACKROCK VA MUNI MONEY MARKET PORTFOLIO Service Shares	61	319	597	1,391

Principal Investment Strategies of the Fund

The Virginia Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the Commonwealth of Virginia or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Virginia municipal securities”). The Fund normally invests at least 80% of its net assets in Virginia municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The Virginia Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• State Specific Risk — The Fund will invest primarily in Virginia municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Virginia municipal securities.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Virginia municipal securities to be subject to state or local income taxation, or the value of Virginia municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the Virginia Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. For the periods October 8, 2003 through May 12, 2005, June 28, 2005 through April 23, 2006, May 3, 2006 through June 1, 2006, and March 12, 2012 through June 30, 2013, there were no Service Shares outstanding. For the periods during which Service Shares were not outstanding, the performance of the Service Shares is based on the return of Institutional Shares, adjusted to reflect the expenses of Service Shares. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.

Service Shares
ANNUAL TOTAL RETURNS
Virginia Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.80% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%. Because there were no Service Shares outstanding during the year-to-date ended June 30, 2013, the year-to-date return as of June 30, 2013 is based on the return of Institutional Shares, adjusted to reflect the expenses of Service Shares.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns	1 Year	5 Years	10 Years
Service BLACKROCK VA MUNI MONEY MARKET PORTFOLIO Service Shares	none	0.32%	1.08%

To obtain the Fund’s current 7-day yield, call (800) 537-4942.

[1] Other Expenses are based on estimated amounts for the current fiscal year. There were no Service Shares outstanding at the end of the most recent fiscal year.

[2] As described in the “Management of the Funds” section of the Fund’s prospectus on pages 46-50, BlackRock Advisors, LLC (“BlackRock”) has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.60% of average daily net assets until August 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 Virginia Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Service | BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Municipal Money Market Portfolio (the “Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax as is consistent with maintaining liquidity and stability of principal.
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 the Municipal Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Municipal Money Market Portfolio seeks to achieve its investment objective by investing at least 80% of its net assets in short-term obligations issued by or on behalf of states, possessions and territories of the United States, their political subdivisions and their agencies (“municipal securities”) and other instruments whose interest, in the opinion of counsel to the issuer of the municipal security or other instrument, is exempt from regular Federal income tax and the Federal alternative minimum tax. The Fund intends to invest so that less than 25% of its total assets are municipal securities of issuers located in the same state. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on state municipal securities to be subject to state or local income taxation, or the value of state municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The information shows you how the Municipal Money Market Portfolio’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) 537-4942
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Service Share ANNUAL TOTAL RETURNS Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.78% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 537-4942.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 537-4942
Service | BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO | Service Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Service Fees	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.33%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.03%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.31%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.72%	[1]
1 Year	rr_ExpenseExampleYear01	$ 74
3 Years	rr_ExpenseExampleYear03	297
5 Years	rr_ExpenseExampleYear05	538
10 Years	rr_ExpenseExampleYear10	$ 1,231
2003	rr_AnnualReturn2003	0.49%
2004	rr_AnnualReturn2004	0.56%
2005	rr_AnnualReturn2005	1.75%
2006	rr_AnnualReturn2006	2.82%
2007	rr_AnnualReturn2007	3.04%
2008	rr_AnnualReturn2008	1.67%
2009	rr_AnnualReturn2009	0.06%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.78%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.34%
10 Years	rr_AverageAnnualReturnYear10	1.03%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.72% of average daily net assets until August 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 Municipal Money Market Portfolio.

XML

Service | BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock U.S. Treasury Money Market Portfolio

Investment Objective

The investment objective of BlackRock U.S. Treasury Money Market Portfolio (the “U.S. Treasury Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income as is consistent with maintaining liquidity and stability of principal.

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 the U.S. Treasury Money Market Portfolio.

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

Annual Fund Operating Expenses		Service BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO Service Shares
Management Fee		0.45%
Service Fees		0.25%
Other Expenses		0.27%
Total Annual Fund Operating Expenses		0.97%
Fee Waivers and/or Expense Reimbursements	[1]	(0.26%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.71%

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	5 Years	10 Years
Service BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO Service Shares	73	283	511	1,166

Principal Investment Strategies of the Fund

The U.S. Treasury Money Market Portfolio seeks to achieve its investment objective by investing 80% of its net assets in short-term bills, notes and other obligations issued or guaranteed by the U.S. Treasury and related repurchase agreements.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The U.S. Treasury Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• Treasury Obligations Risk — Direct obligations of the U.S. Treasury have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• U.S. Government Obligations Risk — Certain securities in which the 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.

Performance Information

The information shows you how the U.S. Treasury Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.

Service Shares
ANNUAL TOTAL RETURNS
U.S. Treasury Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 1.16% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns	1 Year	5 Years	10 Years
Service BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO Service Shares	none	0.24%	1.33%

To obtain the Fund’s current 7-day yield, call (800) 537-4942.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46-50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.71% of average daily net assets until August 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 U.S. Treasury Money Market Portfolio.

XML

Service | BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock Ohio Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock Ohio Municipal Money Market Portfolio (the “Ohio Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Ohio state income tax, as is consistent with maintaining liquidity and stability of principal.

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 the Ohio Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses		Service BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO Service Shares
Management Fee		0.45%
Service Fees		0.25%
Other Expenses		0.34%
Total Annual Fund Operating Expenses		1.04%
Fee Waivers and/or Expense Reimbursements	[1]	(0.35%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.69%

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	5 Years	10 Years
Service BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO Service Shares	70	296	540	1,239

Principal Investment Strategies of the Fund

The Ohio Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of Ohio or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Ohio municipal securities”). The Fund normally invests at least 80% of its net assets in Ohio municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The Ohio Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• State Specific Risk — The Fund will invest primarily in Ohio municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Ohio municipal securities.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Ohio municipal securities to be subject to state or local income taxation, or the value of Ohio municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the Ohio Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.

Service Shares
ANNUAL TOTAL RETURNS
Ohio Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.80% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns	1 Year	5 Years	10 Years
Service BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO Service Shares	none	0.42%	1.12%

To obtain the Fund’s current 7-day yield, call (800) 537-4942.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.69% of average daily net assets until August 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 Ohio Municipal Money Market Portfolio.

XML

Investor A, Institutional | BLACKROCK PA MUNI MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock Pennsylvania Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock Pennsylvania Municipal Money Market Portfolio (the “Pennsylvania Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Pennsylvania personal income tax, as is consistent with maintaining liquidity and stability of principal.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Pennsylvania Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses Investor A, Institutional BLACKROCK PA MUNI MONEY MARKET PORTFOLIO		Investor A Shares	Institutional Shares
Management Fee		0.45%	0.45%
Distribution and/or Service (12b-1) Fees		0.25%	none
Other Expenses		0.64%	0.27%
Total Annual Fund Operating Expenses		1.34%	0.72%
Fee Waivers and/or Expense Reimbursements	[1]	(0.35%)	(0.30%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.99%	0.42%

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 Investor A, Institutional BLACKROCK PA MUNI MONEY MARKET PORTFOLIO (USD $)	1 Year	3 Years	5 Years	10 Years
Investor A Shares	101	390	701	1,582
Institutional Shares	43	200	371	866

Principal Investment Strategies of the Fund

The Pennsylvania Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the Commonwealth of Pennsylvania or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Pennsylvania municipal securities”). The Fund normally invests at least 80% of its net assets in Pennsylvania municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The Pennsylvania Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• State Specific Risk — The Fund will invest primarily in Pennsylvania municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Pennsylvania municipal securities.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Pennsylvania municipal securities to be subject to state or local income taxation, or the value of Pennsylvania municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the Pennsylvania Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Investor A Shares
ANNUAL TOTAL RETURNS
Pennsylvania Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.78% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns Investor A, Institutional BLACKROCK PA MUNI MONEY MARKET PORTFOLIO	1 Year	5 Years	10 Years
Investor A Shares	none	0.32%	1.03%
Institutional Shares	none	0.39%	1.21%

To obtain the Fund’s current 7-day yield, call (800) 441-7762.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.99% (for Investor A Shares) and 0.42% (for Institutional Shares) until August 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 Pennsylvania Municipal Money Market Portfolio.

XML

Investor A, Institutional | BLACKROCK NC MUNI MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock North Carolina Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock North Carolina Municipal Money Market Portfolio (the “North Carolina Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, North Carolina state income tax, as is consistent with maintaining liquidity and stability of principal.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the North Carolina Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses Investor A, Institutional BLACKROCK NC MUNI MONEY MARKET PORTFOLIO		Investor A Shares	Institutional Shares
Management Fee		0.45%	0.45%
Distribution and/or Service (12b-1) Fees		0.25%	none
Other Expenses		0.65%	0.25%
Total Annual Fund Operating Expenses		1.35%	0.70%
Fee Waivers and/or Expense Reimbursements	[1]	(0.48%)	(0.40%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.87%	0.30%

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 Investor A, Institutional BLACKROCK NC MUNI MONEY MARKET PORTFOLIO (USD $)	1 Year	3 Years	5 Years	10 Years
Investor A Shares	89	380	693	1,582
Institutional Shares	31	184	350	833

Principal Investment Strategies of the Fund

The North Carolina Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of North Carolina or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“North Carolina municipal securities”). The Fund normally invests at least 80% of its net assets in North Carolina municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The North Carolina Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.

Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• State Specific Risk — The Fund will invest primarily in North Carolina municipal securities. As a result, the Fund is more exposed to risks affecting issuers of North Carolina municipal securities.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on North Carolina municipal securities to be subject to state or local income taxation, or the value of North Carolina municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the North Carolina Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Investor A Shares
ANNUAL TOTAL RETURNS
North Carolina Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.77% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns Investor A, Institutional BLACKROCK NC MUNI MONEY MARKET PORTFOLIO	1 Year	5 Years	10 Years
Investor A Shares	none	0.31%	1.03%
Institutional Shares	none	0.43%	1.27%

To obtain the Fund’s current 7-day yield, call (800) 441-7762.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.87% (for Investor A Shares) and 0.30% (for Institutional Shares) until August 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 North Carolina Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Document Creation Date	dei_DocumentCreationDate	Jul. 29, 2013

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Investor A, Institutional | BLACKROCK VA MUNI MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Virginia Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Virginia Municipal Money Market Portfolio (the “Virginia Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Virginia state income tax, as is consistent with maintaining liquidity and stability of principal.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Virginia Municipal Money Market 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	August 1, 2014
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	Other Expenses are based on estimated amounts for the current fiscal year.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Virginia Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the Commonwealth of Virginia or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Virginia municipal securities”). The Fund normally invests at least 80% of its net assets in Virginia municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Virginia Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. State Specific Risk — The Fund will invest primarily in Virginia municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Virginia municipal securities. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Virginia municipal securities to be subject to state or local income taxation, or the value of Virginia municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Virginia Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. Because Investor A Shares have not been outstanding since March 12, 2002, the returns shown for Investor A Shares are based on the returns for the Institutional Shares, adjusted to reflect the fees and expenses of Investor A Shares. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting 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 Virginia Municipal Money Market Portfolio’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	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Institutional Shares ANNUAL TOTAL RETURNS Virginia Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.87% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 441-7762.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 441-7762
Investor A, Institutional | BLACKROCK VA MUNI MONEY MARKET PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%	[1]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%	[1]
Other Expenses	rr_OtherExpensesOverAssets	0.49%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.19%	[1]
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.32%)	[1],[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.87%	[1],[2]
1 Year	rr_ExpenseExampleYear01	$ 89
3 Years	rr_ExpenseExampleYear03	346
5 Years	rr_ExpenseExampleYear05	624
10 Years	rr_ExpenseExampleYear10	1,415
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.31%
10 Years	rr_AverageAnnualReturnYear10	0.97%
Investor A, Institutional | BLACKROCK VA MUNI MONEY MARKET PORTFOLIO | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.49%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.94%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.64%)	[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.30%	[2]
1 Year	rr_ExpenseExampleYear01	31
3 Years	rr_ExpenseExampleYear03	236
5 Years	rr_ExpenseExampleYear05	458
10 Years	rr_ExpenseExampleYear10	$ 1,096
2003	rr_AnnualReturn2003	0.37%
2004	rr_AnnualReturn2004	0.39%
2005	rr_AnnualReturn2005	1.57%
2006	rr_AnnualReturn2006	2.76%
2007	rr_AnnualReturn2007	3.08%
2008	rr_AnnualReturn2008	1.86%
2009	rr_AnnualReturn2009	0.17%
2010	rr_AnnualReturn2010	0.02%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.87%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.41%
10 Years	rr_AverageAnnualReturnYear10	1.25%

[1] Other Expenses are based on estimated amounts for the current fiscal year. There were no Investor A Shares in operation during the most recent fiscal year.

[2] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.87% (for Investor A Shares) and 0.30% (for Institutional Shares) until August 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 Virginia Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Investor A, Institutional | BLACKROCK NC MUNI MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock North Carolina Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock North Carolina Municipal Money Market Portfolio (the “North Carolina Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, North Carolina state income tax, as is consistent with maintaining liquidity and stability of principal.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the North Carolina Municipal Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The North Carolina Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of North Carolina or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“North Carolina municipal securities”). The Fund normally invests at least 80% of its net assets in North Carolina municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The North Carolina Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. State Specific Risk — The Fund will invest primarily in North Carolina municipal securities. As a result, the Fund is more exposed to risks affecting issuers of North Carolina municipal securities. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on North Carolina municipal securities to be subject to state or local income taxation, or the value of North Carolina municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the North Carolina Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting 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 North Carolina Municipal Money Market Portfolio’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	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Investor A Shares ANNUAL TOTAL RETURNS North Carolina Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.77% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 441-7762.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 441-7762
Investor A, Institutional | BLACKROCK NC MUNI MONEY MARKET PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.65%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.35%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.48%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.87%	[1]
1 Year	rr_ExpenseExampleYear01	$ 89
3 Years	rr_ExpenseExampleYear03	380
5 Years	rr_ExpenseExampleYear05	693
10 Years	rr_ExpenseExampleYear10	1,582
2003	rr_AnnualReturn2003	0.47%
2004	rr_AnnualReturn2004	0.67%
2005	rr_AnnualReturn2005	1.84%
2006	rr_AnnualReturn2006	2.84%
2007	rr_AnnualReturn2007	2.96%
2008	rr_AnnualReturn2008	1.55%
2009	rr_AnnualReturn2009	0.02%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.77%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.31%
10 Years	rr_AverageAnnualReturnYear10	1.03%
Investor A, Institutional | BLACKROCK NC MUNI MONEY MARKET PORTFOLIO | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.25%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.70%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.40%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.30%	[1]
1 Year	rr_ExpenseExampleYear01	31
3 Years	rr_ExpenseExampleYear03	184
5 Years	rr_ExpenseExampleYear05	350
10 Years	rr_ExpenseExampleYear10	$ 833
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.43%
10 Years	rr_AverageAnnualReturnYear10	1.27%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.87% (for Investor A Shares) and 0.30% (for Institutional Shares) until August 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 North Carolina Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Investor A, Institutional | BLACKROCK PA MUNI MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Pennsylvania Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Pennsylvania Municipal Money Market Portfolio (the “Pennsylvania Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Pennsylvania personal income tax, as is consistent with maintaining liquidity and stability of principal.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Pennsylvania Municipal Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Pennsylvania Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the Commonwealth of Pennsylvania or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Pennsylvania municipal securities”). The Fund normally invests at least 80% of its net assets in Pennsylvania municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Pennsylvania Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. State Specific Risk — The Fund will invest primarily in Pennsylvania municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Pennsylvania municipal securities. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Pennsylvania municipal securities to be subject to state or local income taxation, or the value of Pennsylvania municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Pennsylvania Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting 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 Pennsylvania Municipal Money Market Portfolio’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	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Investor A Shares ANNUAL TOTAL RETURNS Pennsylvania Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.78% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 441-7762.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 441-7762
Investor A, Institutional | BLACKROCK PA MUNI MONEY MARKET PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.64%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.34%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.35%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.99%	[1]
1 Year	rr_ExpenseExampleYear01	$ 101
3 Years	rr_ExpenseExampleYear03	390
5 Years	rr_ExpenseExampleYear05	701
10 Years	rr_ExpenseExampleYear10	1,582
2003	rr_AnnualReturn2003	0.42%
2004	rr_AnnualReturn2004	0.64%
2005	rr_AnnualReturn2005	1.84%
2006	rr_AnnualReturn2006	2.81%
2007	rr_AnnualReturn2007	3.02%
2008	rr_AnnualReturn2008	1.56%
2009	rr_AnnualReturn2009	0.04%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.78%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.32%
10 Years	rr_AverageAnnualReturnYear10	1.03%
Investor A, Institutional | BLACKROCK PA MUNI MONEY MARKET PORTFOLIO | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.27%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.72%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.30%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.42%	[1]
1 Year	rr_ExpenseExampleYear01	43
3 Years	rr_ExpenseExampleYear03	200
5 Years	rr_ExpenseExampleYear05	371
10 Years	rr_ExpenseExampleYear10	$ 866
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.39%
10 Years	rr_AverageAnnualReturnYear10	1.21%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.99% (for Investor A Shares) and 0.42% (for Institutional Shares) until August 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 Pennsylvania Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Investor A, Institutional | BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock New Jersey Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock New Jersey Municipal Money Market Portfolio (the “New Jersey Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, New Jersey state income tax, as is consistent with maintaining liquidity and stability of principal.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the New Jersey Municipal Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The New Jersey Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of New Jersey or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“New Jersey municipal securities”). The Fund normally invests at least 80% of its net assets in New Jersey municipal securities. In addition, the Fund normally invests at least 80% of its assets in New Jersey municipal securities and other obligations which, in bond counsel’s opinion, are statutorily free from state and local taxation under the laws of New Jersey or the U.S. in order to qualify as a “qualified investment fund” under New Jersey law. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The New Jersey Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. State Specific Risk — The Fund will invest primarily in New Jersey municipal securities. As a result, the Fund is more exposed to risks affecting issuers of New Jersey municipal securities. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on New Jersey municipal securities to be subject to state or local income taxation, or the value of New Jersey municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the New Jersey Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting 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 New Jersey Municipal Money Market Portfolio’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	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Investor A Shares ANNUAL TOTAL RETURNS New Jersey Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.77% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 441-7762.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 441-7762
Investor A, Institutional | BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.62%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.32%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.36%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.96%	[1]
1 Year	rr_ExpenseExampleYear01	$ 98
3 Years	rr_ExpenseExampleYear03	383
5 Years	rr_ExpenseExampleYear05	689
10 Years	rr_ExpenseExampleYear10	1,559
2003	rr_AnnualReturn2003	0.38%
2004	rr_AnnualReturn2004	0.56%
2005	rr_AnnualReturn2005	1.71%
2006	rr_AnnualReturn2006	2.78%
2007	rr_AnnualReturn2007	3.00%
2008	rr_AnnualReturn2008	1.69%
2009	rr_AnnualReturn2009	0.13%
2010	rr_AnnualReturn2010	0.01%
2011	rr_AnnualReturn2011	0.01%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.77%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.36%
10 Years	rr_AverageAnnualReturnYear10	1.02%
Investor A, Institutional | BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.40%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.85%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.46%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.39%	[1]
1 Year	rr_ExpenseExampleYear01	40
3 Years	rr_ExpenseExampleYear03	225
5 Years	rr_ExpenseExampleYear05	426
10 Years	rr_ExpenseExampleYear10	$ 1,006
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.47%
10 Years	rr_AverageAnnualReturnYear10	1.24%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.96% (for Investor A Shares) and 0.39% (for Institutional Shares) until August 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 New Jersey Municipal Money Market Portfolio.

XML

Investor A, Institutional | BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock U.S. Treasury Money Market Portfolio

Investment Objective

The investment objective of BlackRock U.S. Treasury Money Market Portfolio (the “U.S. Treasury Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income as is consistent with maintaining liquidity and stability of principal.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the U.S. Treasury Money Market Portfolio.

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

Annual Fund Operating Expenses Investor A, Institutional BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO		Investor A Shares	Institutional Shares
Management Fee		0.45%	0.45%
Distribution and/or Service (12b-1) Fees		0.25%	none
Other Expenses		0.22%	0.30%
Total Annual Fund Operating Expenses		0.92%	0.75%
Fee Waivers and/or Expense Reimbursements	[1]	(0.04%)	(0.34%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.88%	0.41%

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 Investor A, Institutional BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO (USD $)	1 Year	3 Years	5 Years	10 Years
Investor A Shares	90	289	505	1,128
Institutional Shares	42	206	383	898

Principal Investment Strategies of the Fund

The U.S. Treasury Money Market Portfolio seeks to achieve its investment objective by investing 80% of its net assets in short-term bills, notes and other obligations issued or guaranteed by the U.S. Treasury and related repurchase agreements.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The U.S. Treasury Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• Treasury Obligations Risk — Direct obligations of the U.S. Treasury have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• U.S. Government Obligations Risk — Certain securities in which the 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.

Performance Information

The information shows you how the U.S. Treasury Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Investor A Shares
ANNUAL TOTAL RETURNS
U.S. Treasury Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 1.16% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns Investor A, Institutional BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO	1 Year	5 Years	10 Years
Investor A Shares	none	0.24%	1.30%
Institutional Shares	none	0.29%	1.51%

To obtain the Fund’s current 7-day yield, call (800) 441-7762.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.88% (for Investor A Shares) and 0.41% (for Institutional Shares) until August 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 U.S. Treasury Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Service | BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock New Jersey Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock New Jersey Municipal Money Market Portfolio (the “New Jersey Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, New Jersey state income tax, as is consistent with maintaining liquidity and stability of principal.
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 the New Jersey Municipal Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The New Jersey Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of New Jersey or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“New Jersey municipal securities”). The Fund normally invests at least 80% of its net assets in New Jersey municipal securities. In addition, the Fund normally invests at least 80% of its assets in New Jersey municipal securities and other obligations which, in bond counsel’s opinion, are statutorily free from state and local taxation under the laws of New Jersey or the U.S. in order to qualify as a “qualified investment fund” under New Jersey law. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The New Jersey Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. State Specific Risk — The Fund will invest primarily in New Jersey municipal securities. As a result, the Fund is more exposed to risks affecting issuers of New Jersey municipal securities. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on New Jersey municipal securities to be subject to state or local income taxation, or the value of New Jersey municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the New Jersey Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The information shows you how the New Jersey Municipal Money Market Portfolio’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) 537-4942
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Service Shares ANNUAL TOTAL RETURNS New Jersey Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.77% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 537-4942.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 537-4942
Service | BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO | Service Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Service Fees	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.30%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.00%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.31%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.69%	[1]
1 Year	rr_ExpenseExampleYear01	$ 70
3 Years	rr_ExpenseExampleYear03	288
5 Years	rr_ExpenseExampleYear05	522
10 Years	rr_ExpenseExampleYear10	$ 1,196
2003	rr_AnnualReturn2003	0.48%
2004	rr_AnnualReturn2004	0.58%
2005	rr_AnnualReturn2005	1.76%
2006	rr_AnnualReturn2006	2.78%
2007	rr_AnnualReturn2007	3.00%
2008	rr_AnnualReturn2008	1.69%
2009	rr_AnnualReturn2009	0.10%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.77%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.36%
10 Years	rr_AverageAnnualReturnYear10	1.03%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.69% of average daily net assets until August 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 New Jersey Municipal Money Market Portfolio.

XML

Investor A, Institutional | BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock Ohio Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock Ohio Municipal Money Market Portfolio (the “Ohio Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Ohio state income tax, as is consistent with maintaining liquidity and stability of principal.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Ohio Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses Investor A, Institutional BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO		Investor A Shares	Institutional Shares
Management Fee		0.45%	0.45%
Distribution and/or Service (12b-1) Fees		0.25%	none
Other Expenses		4.00%	0.34%
Total Annual Fund Operating Expenses		4.70%	0.79%
Fee Waivers and/or Expense Reimbursements	[1]	(3.74%)	(0.40%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.96%	0.39%

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 Investor A, Institutional BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO (USD $)	1 Year	3 Years	5 Years	10 Years
Investor A Shares	98	1,079	2,066	4,559
Institutional Shares	40	201	377	941

Principal Investment Strategies of the Fund

The Ohio Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of Ohio or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Ohio municipal securities”). The Fund normally invests at least 80% of its net assets in Ohio municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The Ohio Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• State Specific Risk — The Fund will invest primarily in Ohio municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Ohio municipal securities.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Ohio municipal securities to be subject to state or local income taxation, or the value of Ohio municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the Ohio Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Investor A Shares
ANNUAL TOTAL RETURNS
Ohio Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.80% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns Investor A, Institutional BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO	1 Year	5 Years	10 Years
Investor A Shares	none	0.43%	1.10%
Institutional Shares	none	0.54%	1.33%

To obtain the Fund’s current 7-day yield, call (800) 441-7762.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.96% (for Investor A Shares) and 0.39% (for Institutional Shares) until August 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 Ohio Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Investor A, Institutional | BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Ohio Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Ohio Municipal Money Market Portfolio (the “Ohio Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Ohio state income tax, as is consistent with maintaining liquidity and stability of principal.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Ohio Municipal Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Ohio Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of Ohio or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Ohio municipal securities”). The Fund normally invests at least 80% of its net assets in Ohio municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Ohio Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. State Specific Risk — The Fund will invest primarily in Ohio municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Ohio municipal securities. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Ohio municipal securities to be subject to state or local income taxation, or the value of Ohio municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Ohio Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting 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 Ohio Municipal Money Market Portfolio’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	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Investor A Shares ANNUAL TOTAL RETURNS Ohio Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.80% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 441-7762.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 441-7762
Investor A, Institutional | BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	4.00%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	4.70%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(3.74%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.96%	[1]
1 Year	rr_ExpenseExampleYear01	$ 98
3 Years	rr_ExpenseExampleYear03	1,079
5 Years	rr_ExpenseExampleYear05	2,066
10 Years	rr_ExpenseExampleYear10	4,559
2003	rr_AnnualReturn2003	0.46%
2004	rr_AnnualReturn2004	0.63%
2005	rr_AnnualReturn2005	1.82%
2006	rr_AnnualReturn2006	2.89%
2007	rr_AnnualReturn2007	3.10%
2008	rr_AnnualReturn2008	1.92%
2009	rr_AnnualReturn2009	0.22%
2010	rr_AnnualReturn2010	0.02%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.80%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.43%
10 Years	rr_AverageAnnualReturnYear10	1.10%
Investor A, Institutional | BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.34%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.79%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.40%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.39%	[1]
1 Year	rr_ExpenseExampleYear01	40
3 Years	rr_ExpenseExampleYear03	201
5 Years	rr_ExpenseExampleYear05	377
10 Years	rr_ExpenseExampleYear10	$ 941
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.54%
10 Years	rr_AverageAnnualReturnYear10	1.33%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.96% (for Investor A Shares) and 0.39% (for Institutional Shares) until August 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 Ohio Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Service | BLACKROCK MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Money Market Portfolio (the “Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income as is consistent with maintaining liquidity and stability of principal.
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 the Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Money Market Portfolio seeks to achieve its investment objective by investing in a broad range of short-term, high quality U.S. dollar-denominated money market instruments, including government, U.S. and foreign bank, commercial and other obligations. Under normal market conditions, at least 25% of the Fund’s total assets will be invested in obligations of issuers in the financial services industry or in obligations, such as repurchase agreements, secured by such obligations. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Asset-Backed Securities Risk — Asset-backed securities represent interests in “pools” of assets, including consumer loans or receivables held in trust. 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 asset, particularly during periods of economic downturn. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. 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. Financial Services Industry Risk — The profitability of many types of financial services companies may be adversely affected in certain market cycles, including periods of rising interest rates, which may restrict the availability and increase the cost of capital, and declining economic conditions, which may cause credit losses due to financial difficulties of borrowers. Because many types of financial services companies are vulnerable to these economic cycles, a large portion of the Fund’s investments may lose value during such periods. Foreign Securities Risk — Foreign securities risk is the risk that the Fund may have difficulty buying and selling on foreign exchanges. In addition, prices of foreign securities may go up and down more than prices of securities traded in the United States. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Prepayment Risk — When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. U.S. Government Obligations Risk — Certain securities in which the 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.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The information shows you how the Money Market Portfolio’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) 537-4942
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Service Shares ANNUAL TOTAL RETURNS Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 1.20% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 537-4942.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 537-4942
Service | BLACKROCK MONEY MARKET PORTFOLIO | Service Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.43%
Service Fees	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.26%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.94%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.22%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.72%	[1]
1 Year	rr_ExpenseExampleYear01	$ 74
3 Years	rr_ExpenseExampleYear03	278
5 Years	rr_ExpenseExampleYear05	499
10 Years	rr_ExpenseExampleYear10	$ 1,135
2003	rr_AnnualReturn2003	0.58%
2004	rr_AnnualReturn2004	0.74%
2005	rr_AnnualReturn2005	2.60%
2006	rr_AnnualReturn2006	4.48%
2007	rr_AnnualReturn2007	4.76%
2008	rr_AnnualReturn2008	2.65%
2009	rr_AnnualReturn2009	0.20%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	1.20%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.57%
10 Years	rr_AverageAnnualReturnYear10	1.59%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.72% of average daily net assets until August 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 Money Market Portfolio.

XML

Service | BLACKROCK MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock Money Market Portfolio

Investment Objective

The investment objective of BlackRock Money Market Portfolio (the “Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income as is consistent with maintaining liquidity and stability of principal.

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 the Money Market Portfolio.

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

Annual Fund Operating Expenses		Service BLACKROCK MONEY MARKET PORTFOLIO Service Shares
Management Fee		0.43%
Service Fees		0.25%
Other Expenses		0.26%
Total Annual Fund Operating Expenses		0.94%
Fee Waivers and/or Expense Reimbursements	[1]	(0.22%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.72%

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	5 Years	10 Years
Service BLACKROCK MONEY MARKET PORTFOLIO Service Shares	74	278	499	1,135

Principal Investment Strategies of the Fund

The Money Market Portfolio seeks to achieve its investment objective by investing in a broad range of short-term, high quality U.S. dollar-denominated money market instruments, including government, U.S. and foreign bank, commercial and other obligations. Under normal market conditions, at least 25% of the Fund’s total assets will be invested in obligations of issuers in the financial services industry or in obligations, such as repurchase agreements, secured by such obligations.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Asset-Backed Securities Risk — Asset-backed securities represent interests in “pools” of assets, including consumer loans or receivables held in trust. 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 asset, particularly during periods of economic downturn.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• 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.

• Financial Services Industry Risk — The profitability of many types of financial services companies may be adversely affected in certain market cycles, including periods of rising interest rates, which may restrict the availability and increase the cost of capital, and declining economic conditions, which may cause credit losses due to financial difficulties of borrowers. Because many types of financial services companies are vulnerable to these economic cycles, a large portion of the Fund’s investments may lose value during such periods.

• Foreign Securities Risk — Foreign securities risk is the risk that the Fund may have difficulty buying and selling on foreign exchanges. In addition, prices of foreign securities may go up and down more than prices of securities traded in the United States.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

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

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• U.S. Government Obligations Risk — Certain securities in which the 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.

Performance Information

The information shows you how the Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.

Service Shares
ANNUAL TOTAL RETURNS
Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 1.20% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns	1 Year	5 Years	10 Years
Service BLACKROCK MONEY MARKET PORTFOLIO Service Shares	none	0.57%	1.59%

To obtain the Fund’s current 7-day yield, call (800) 537-4942.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.72% of average daily net assets until August 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 Money Market Portfolio.

XML

Investor A, Institutional | BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock Municipal Money Market Portfolio (the “Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax as is consistent with maintaining liquidity and stability of principal.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses Investor A, Institutional BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO		Investor A Shares	Institutional Shares
Management Fee		0.45%	0.45%
Distribution and/or Service (12b-1) Fees		0.25%	none
Other Expenses		0.29%	0.34%
Total Annual Fund Operating Expenses		0.99%	0.79%
Fee Waivers and/or Expense Reimbursements	[1]	(0.10%)	(0.37%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.89%	0.42%

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 Investor A, Institutional BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO (USD $)	1 Year	3 Years	5 Years	10 Years
Investor A Shares	91	305	537	1,204
Institutional Shares	43	215	402	943

Principal Investment Strategies of the Fund

The Municipal Money Market Portfolio seeks to achieve its investment objective by investing at least 80% of its net assets in short-term obligations issued by or on behalf of states, possessions and territories of the United States, their political subdivisions and their agencies (“municipal securities”) and other instruments whose interest, in the opinion of counsel to the issuer of the municipal security or other instrument, is exempt from regular Federal income tax and the Federal alternative minimum tax. The Fund intends to invest so that less than 25% of its total assets are municipal securities of issuers located in the same state. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on state municipal securities to be subject to state or local income taxation, or the value of state municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Investor A Shares
ANNUAL TOTAL RETURNS
Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.78% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns Investor A, Institutional BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO	1 Year	5 Years	10 Years
Investor A Shares	none	0.35%	1.02%
Institutional Shares	none	0.44%	1.23%

To obtain the Fund’s current 7-day yield, call (800) 441-7762.

[1] As described in the “Management of the Funds” section of the Fund’s prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.89% (for Investor A Shares) and 0.42% (for Institutional Shares) until August 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 Municipal Money Market Portfolio.

XML

Investor A, B, C and Institutional | BLACKROCK MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock Money Market Portfolio

Investment Objective

The investment objective of BlackRock Money Market Portfolio (the “Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income as is consistent with maintaining liquidity and stability of principal.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Money Market Portfolio.

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

Annual Fund Operating Expenses Investor A, B, C and Institutional BLACKROCK MONEY MARKET PORTFOLIO		Investor A Shares	Investor B Shares	Investor C Shares	Institutional Shares
Management Fee		0.43%	0.43%	0.43%	0.43%
Distribution and/or Service (12b-1) Fees		0.25%	1.00%	1.00%	none
Other Expenses		0.23%	0.27%	0.17%	0.27%
Total Annual Fund Operating Expenses		0.91%	1.70%	1.60%	0.70%
Fee Waivers and/or Expense Reimbursements	[1]	(0.02%)	(0.21%)	(0.11%)	(0.28%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.89%	1.49%	1.49%	0.42%

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 Investor A, B, C and Institutional BLACKROCK MONEY MARKET PORTFOLIO (USD $)		1 Year	3 Years	5 Years	10 Years	10 Years		10 Years		10 Years
Investor A Shares		91	288	502	1,118
Investor B Shares	[1]	152	515	903		1,781	[2]	1,682	[3]	1,991	[4]
Investor C Shares	[1]	152	494	860	1,891
Institutional Shares		43	196	362	844

Principal Investment Strategies of the Fund

The Money Market Portfolio seeks to achieve its investment objective by investing in a broad range of short-term, high quality U.S. dollar-denominated money market instruments, including government, U.S. and foreign bank, commercial and other obligations. Under normal market conditions, at least 25% of the Fund’s total assets will be invested in obligations of issuers in the financial services industry or in obligations, such as repurchase agreements, secured by such obligations.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Asset-Backed Securities Risk — Asset-backed securities represent interests in “pools” of assets, including consumer loans or receivables held in trust. 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 asset, particularly during periods of economic downturn.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• 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.

• Financial Services Industry Risk — The profitability of many types of financial services companies may be adversely affected in certain market cycles, including periods of rising interest rates, which may restrict the availability and increase the cost of capital, and declining economic conditions, which may cause credit losses due to financial difficulties of borrowers. Because many types of financial services companies are vulnerable to these economic cycles, a large portion of the Fund’s investments may lose value during such periods.

• Foreign Securities Risk — Foreign securities risk is the risk that the Fund may have difficulty buying and selling on foreign exchanges. In addition, prices of foreign securities may go up and down more than prices of securities traded in the United States.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.

Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

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

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• U.S. Government Obligations Risk — Certain securities in which the 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.

Performance Information

The information shows you how the Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Investor A Shares
ANNUAL TOTAL RETURNS
Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 1.18% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns Investor A, B, C and Institutional BLACKROCK MONEY MARKET PORTFOLIO	1 Year	5 Years	10 Years
Investor A Shares	none	0.55%	1.53%
Investor B Shares	none	0.39%	1.25%
Investor C Shares	none	0.40%	1.25%
Institutional Shares	none	0.66%	1.78%

To obtain the Fund’s current 7-day yield, call (800) 441-7762.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53-57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.89% (for Investor A Shares), 1.49% (for Investor B and Investor C Shares) and 0.42% (for Institutional Shares) until August 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 Money Market Portfolio.

[1] These expense figures do not reflect the imposition of the deferred sales charge which may be deducted upon the redemption of Investor B or Investor C Shares of the Fund received in an exchange transaction for Investor B or Investor C Shares of a non-money market fund advised by BlackRock or its affiliates (each, a "Non-Money Market BlackRock Fund") as described in the applicable prospectuses. No deferred sales charge is deducted upon the redemption of Investor B or Investor C Shares of the Fund that are purchased from the Trust and not acquired by exchange.

[2] Based on the conversion of Investor B Shares to Investor A Shares after eight years (applies to shares received in an exchange transaction for Investor B Shares of certain equity Non-Money Market BlackRock Funds).

[3] Based on the conversion of Investor B Shares to Investor A Shares after seven years (applies to shares received in an exchange transaction for Investor B Shares of certain fixed-income Non-Money Market BlackRock Funds).

[4] Based on the conversion of Investor B Shares to Investor A Shares after ten years (applies to shares received in an exchange transaction for Investor B Shares of certain fixed-income Non-Money Market BlackRock Funds).

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Service | BLACKROCK NC MUNI MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock North Carolina Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock North Carolina Municipal Money Market Portfolio (the “North Carolina Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, North Carolina state income tax, as is consistent with maintaining liquidity and stability of principal.
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 the North Carolina Municipal Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The North Carolina Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of North Carolina or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“North Carolina municipal securities”). The Fund normally invests at least 80% of its net assets in North Carolina municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The North Carolina Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. State Specific Risk — The Fund will invest primarily in North Carolina municipal securities. As a result, the Fund is more exposed to risks affecting issuers of North Carolina municipal securities. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on North Carolina municipal securities to be subject to state or local income taxation, or the value of North Carolina municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the North Carolina Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The information shows you how the North Carolina Municipal Money Market Portfolio’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) 537-4942
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Service Shares ANNUAL TOTAL RETURNS North Carolina Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.79% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 537-4942.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 537-4942
Service | BLACKROCK NC MUNI MONEY MARKET PORTFOLIO | Service Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Service Fees	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.40%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.10%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.50%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.60%	[1]
1 Year	rr_ExpenseExampleYear01	$ 61
3 Years	rr_ExpenseExampleYear03	300
5 Years	rr_ExpenseExampleYear05	558
10 Years	rr_ExpenseExampleYear10	$ 1,295
2003	rr_AnnualReturn2003	0.56%
2004	rr_AnnualReturn2004	0.68%
2005	rr_AnnualReturn2005	1.88%
2006	rr_AnnualReturn2006	2.91%
2007	rr_AnnualReturn2007	3.09%
2008	rr_AnnualReturn2008	1.69%
2009	rr_AnnualReturn2009	0.07%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.79%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.35%
10 Years	rr_AverageAnnualReturnYear10	1.08%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.60% of average daily net assets until August 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 North Carolina Municipal Money Market Portfolio.

XML

Investor A, Institutional | BLACKROCK VA MUNI MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock Virginia Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock Virginia Municipal Money Market Portfolio (the “Virginia Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Virginia state income tax, as is consistent with maintaining liquidity and stability of principal.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Virginia Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses Investor A, Institutional BLACKROCK VA MUNI MONEY MARKET PORTFOLIO		Investor A Shares		Institutional Shares
Management Fee		0.45%	[1]	0.45%
Distribution and/or Service (12b-1) Fees		0.25%	[1]	none
Other Expenses		0.49%	[1]	0.49%
Total Annual Fund Operating Expenses		1.19%	[1]	0.94%
Fee Waivers and/or Expense Reimbursements	[2]	(0.32%)	[1]	(0.64%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[2]	0.87%	[1]	0.30%

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 Investor A, Institutional BLACKROCK VA MUNI MONEY MARKET PORTFOLIO (USD $)	1 Year	3 Years	5 Years	10 Years
Investor A Shares	89	346	624	1,415
Institutional Shares	31	236	458	1,096

Principal Investment Strategies of the Fund

The Virginia Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the Commonwealth of Virginia or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Virginia municipal securities”). The Fund normally invests at least 80% of its net assets in Virginia municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The Virginia Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• State Specific Risk — The Fund will invest primarily in Virginia municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Virginia municipal securities.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Virginia municipal securities to be subject to state or local income taxation, or the value of Virginia municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the Virginia Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. Because Investor A Shares have not been outstanding since March 12, 2002, the returns shown for Investor A Shares are based on the returns for the Institutional Shares, adjusted to reflect the fees and expenses of Investor A Shares. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Institutional Shares
ANNUAL TOTAL RETURNS
Virginia Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.87% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns Investor A, Institutional BLACKROCK VA MUNI MONEY MARKET PORTFOLIO	1 Year	5 Years	10 Years
Investor A Shares	none	0.31%	0.97%
Institutional Shares	none	0.41%	1.25%

To obtain the Fund’s current 7-day yield, call (800) 441-7762.

[1] Other Expenses are based on estimated amounts for the current fiscal year. There were no Investor A Shares in operation during the most recent fiscal year.

[2] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.87% (for Investor A Shares) and 0.30% (for Institutional Shares) until August 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 Virginia Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Investor A, Institutional | BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock U.S. Treasury Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock U.S. Treasury Money Market Portfolio (the “U.S. Treasury Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income as is consistent with maintaining liquidity and stability of principal.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the U.S. Treasury Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The U.S. Treasury Money Market Portfolio seeks to achieve its investment objective by investing 80% of its net assets in short-term bills, notes and other obligations issued or guaranteed by the U.S. Treasury and related repurchase agreements. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The U.S. Treasury Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. Treasury Obligations Risk — Direct obligations of the U.S. Treasury have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. U.S. Government Obligations Risk — Certain securities in which the 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.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the U.S. Treasury Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting 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 U.S. Treasury Money Market Portfolio’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	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Investor A Shares ANNUAL TOTAL RETURNS U.S. Treasury Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 1.16% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 441-7762.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 441-7762
Investor A, Institutional | BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.22%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.92%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.04%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.88%	[1]
1 Year	rr_ExpenseExampleYear01	$ 90
3 Years	rr_ExpenseExampleYear03	289
5 Years	rr_ExpenseExampleYear05	505
10 Years	rr_ExpenseExampleYear10	1,128
2003	rr_AnnualReturn2003	0.31%
2004	rr_AnnualReturn2004	0.54%
2005	rr_AnnualReturn2005	2.43%
2006	rr_AnnualReturn2006	4.32%
2007	rr_AnnualReturn2007	4.33%
2008	rr_AnnualReturn2008	1.19%
2009	rr_AnnualReturn2009	0.01%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2006
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	1.16%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.24%
10 Years	rr_AverageAnnualReturnYear10	1.30%
Investor A, Institutional | BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.30%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.75%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.34%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.41%	[1]
1 Year	rr_ExpenseExampleYear01	42
3 Years	rr_ExpenseExampleYear03	206
5 Years	rr_ExpenseExampleYear05	383
10 Years	rr_ExpenseExampleYear10	$ 898
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.29%
10 Years	rr_AverageAnnualReturnYear10	1.51%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.88% (for Investor A Shares) and 0.41% (for Institutional Shares) until August 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 U.S. Treasury Money Market Portfolio.

XML

Service | BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock Municipal Money Market Portfolio (the “Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax as is consistent with maintaining liquidity and stability of principal.

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 the Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses		Service BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO Service Shares
Management Fee		0.45%
Service Fees		0.25%
Other Expenses		0.33%
Total Annual Fund Operating Expenses		1.03%
Fee Waivers and/or Expense Reimbursements	[1]	(0.31%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.72%

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	5 Years	10 Years
Service BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO Service Shares	74	297	538	1,231

Principal Investment Strategies of the Fund

The Municipal Money Market Portfolio seeks to achieve its investment objective by investing at least 80% of its net assets in short-term obligations issued by or on behalf of states, possessions and territories of the United States, their political subdivisions and their agencies (“municipal securities”) and other instruments whose interest, in the opinion of counsel to the issuer of the municipal security or other instrument, is exempt from regular Federal income tax and the Federal alternative minimum tax. The Fund intends to invest so that less than 25% of its total assets are municipal securities of issuers located in the same state. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on state municipal securities to be subject to state or local income taxation, or the value of state municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.

Service Share
ANNUAL TOTAL RETURNS
Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.78% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns	1 Year	5 Years	10 Years
Service BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO Service Shares	none	0.34%	1.03%

To obtain the Fund’s current 7-day yield, call (800) 537-4942.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.72% of average daily net assets until August 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 Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Service | BLACKROCK PA MUNI MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Pennsylvania Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Pennsylvania Municipal Money Market Portfolio (the “Pennsylvania Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Pennsylvania personal income tax, as is consistent with maintaining liquidity and stability of principal.
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 the Pennsylvania Municipal Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Pennsylvania Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the Commonwealth of Pennsylvania or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Pennsylvania municipal securities”). The Fund normally invests at least 80% of its net assets in Pennsylvania municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Pennsylvania Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. State Specific Risk — The Fund will invest primarily in Pennsylvania municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Pennsylvania municipal securities. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Pennsylvania municipal securities to be subject to state or local income taxation, or the value of Pennsylvania municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Pennsylvania Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The information shows you how the Pennsylvania Municipal Money Market Portfolio’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) 537-4942
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Service Shares ANNUAL TOTAL RETURNS Pennsylvania Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.78% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 537-4942.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 537-4942
Service | BLACKROCK PA MUNI MONEY MARKET PORTFOLIO | Service Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Service Fees	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.28%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.98%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.26%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.72%	[1]
1 Year	rr_ExpenseExampleYear01	$ 74
3 Years	rr_ExpenseExampleYear03	286
5 Years	rr_ExpenseExampleYear05	516
10 Years	rr_ExpenseExampleYear10	$ 1,178
2003	rr_AnnualReturn2003	0.51%
2004	rr_AnnualReturn2004	0.58%
2005	rr_AnnualReturn2005	1.80%
2006	rr_AnnualReturn2006	2.83%
2007	rr_AnnualReturn2007	3.03%
2008	rr_AnnualReturn2008	1.55%
2009	rr_AnnualReturn2009	0.02%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.78%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.31%
10 Years	rr_AverageAnnualReturnYear10	1.03%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.72% of average daily net assets until August 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 Pennsylvania Municipal Money Market Portfolio.

XML

Service | BLACKROCK NC MUNI MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock North Carolina Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock North Carolina Municipal Money Market Portfolio (the “North Carolina Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, North Carolina state income tax, as is consistent with maintaining liquidity and stability of principal.

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 the North Carolina Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses		Service BLACKROCK NC MUNI MONEY MARKET PORTFOLIO Service Shares
Management Fee		0.45%
Service Fees		0.25%
Other Expenses		0.40%
Total Annual Fund Operating Expenses		1.10%
Fee Waivers and/or Expense Reimbursements	[1]	(0.50%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.60%

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	5 Years	10 Years
Service BLACKROCK NC MUNI MONEY MARKET PORTFOLIO Service Shares	61	300	558	1,295

Principal Investment Strategies of the Fund

The North Carolina Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of North Carolina or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“North Carolina municipal securities”). The Fund normally invests at least 80% of its net assets in North Carolina municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The North Carolina Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• State Specific Risk — The Fund will invest primarily in North Carolina municipal securities. As a result, the Fund is more exposed to risks affecting issuers of North Carolina municipal securities.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on North Carolina municipal securities to be subject to state or local income taxation, or the value of North Carolina municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the North Carolina Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.

Service Shares
ANNUAL TOTAL RETURNS
North Carolina Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.79% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns	1 Year	5 Years	10 Years
Service BLACKROCK NC MUNI MONEY MARKET PORTFOLIO Service Shares	none	0.35%	1.08%

To obtain the Fund’s current 7-day yield, call (800) 537-4942.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.60% of average daily net assets until August 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 North Carolina Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Investor A, B, C and Institutional | BLACKROCK MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Money Market Portfolio (the “Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income as is consistent with maintaining liquidity and stability of principal.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Money Market Portfolio seeks to achieve its investment objective by investing in a broad range of short-term, high quality U.S. dollar-denominated money market instruments, including government, U.S. and foreign bank, commercial and other obligations. Under normal market conditions, at least 25% of the Fund’s total assets will be invested in obligations of issuers in the financial services industry or in obligations, such as repurchase agreements, secured by such obligations. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Asset-Backed Securities Risk — Asset-backed securities represent interests in “pools” of assets, including consumer loans or receivables held in trust. 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 asset, particularly during periods of economic downturn. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. 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. Financial Services Industry Risk — The profitability of many types of financial services companies may be adversely affected in certain market cycles, including periods of rising interest rates, which may restrict the availability and increase the cost of capital, and declining economic conditions, which may cause credit losses due to financial difficulties of borrowers. Because many types of financial services companies are vulnerable to these economic cycles, a large portion of the Fund’s investments may lose value during such periods. Foreign Securities Risk — Foreign securities risk is the risk that the Fund may have difficulty buying and selling on foreign exchanges. In addition, prices of foreign securities may go up and down more than prices of securities traded in the United States. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Prepayment Risk — When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. U.S. Government Obligations Risk — Certain securities in which the 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.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting 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 Money Market Portfolio’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	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Investor A Shares ANNUAL TOTAL RETURNS Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 1.18% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 441-7762.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 441-7762
Investor A, B, C and Institutional | BLACKROCK MONEY MARKET PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.43%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.23%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.91%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.02%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.89%	[1]
1 Year	rr_ExpenseExampleYear01	$ 91
3 Years	rr_ExpenseExampleYear03	288
5 Years	rr_ExpenseExampleYear05	502
10 Years	rr_ExpenseExampleYear10	1,118
2003	rr_AnnualReturn2003	0.41%
2004	rr_AnnualReturn2004	0.68%
2005	rr_AnnualReturn2005	2.56%
2006	rr_AnnualReturn2006	4.39%
2007	rr_AnnualReturn2007	4.68%
2008	rr_AnnualReturn2008	2.59%
2009	rr_AnnualReturn2009	0.18%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	1.18%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.55%
10 Years	rr_AverageAnnualReturnYear10	1.53%
Investor A, B, C and Institutional | BLACKROCK MONEY MARKET PORTFOLIO | Investor B Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.43%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.27%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.70%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.21%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	1.49%	[1]
1 Year	rr_ExpenseExampleYear01	152	[2]
3 Years	rr_ExpenseExampleYear03	515	[2]
5 Years	rr_ExpenseExampleYear05	903	[2]
10 Years	bf1_ExpenseExampleYearTenAfterEight	1,781	[2],[3]
10 Years	bf1_ExpenseExampleYearTenAfterSeven	1,682	[2],[4]
10 Years	bf1_ExpenseExampleYearTenAfterTen	1,991	[2],[5]
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.39%
10 Years	rr_AverageAnnualReturnYear10	1.25%
Investor A, B, C and Institutional | BLACKROCK MONEY MARKET PORTFOLIO | Investor C Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.43%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.17%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.60%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.11%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	1.49%	[1]
1 Year	rr_ExpenseExampleYear01	152	[2]
3 Years	rr_ExpenseExampleYear03	494	[2]
5 Years	rr_ExpenseExampleYear05	860	[2]
10 Years	rr_ExpenseExampleYear10	1,891	[2]
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.40%
10 Years	rr_AverageAnnualReturnYear10	1.25%
Investor A, B, C and Institutional | BLACKROCK MONEY MARKET PORTFOLIO | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.43%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.27%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.70%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.28%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.42%	[1]
1 Year	rr_ExpenseExampleYear01	43
3 Years	rr_ExpenseExampleYear03	196
5 Years	rr_ExpenseExampleYear05	362
10 Years	rr_ExpenseExampleYear10	$ 844
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.66%
10 Years	rr_AverageAnnualReturnYear10	1.78%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53-57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.89% (for Investor A Shares), 1.49% (for Investor B and Investor C Shares) and 0.42% (for Institutional Shares) until August 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 Money Market Portfolio.

[2] These expense figures do not reflect the imposition of the deferred sales charge which may be deducted upon the redemption of Investor B or Investor C Shares of the Fund received in an exchange transaction for Investor B or Investor C Shares of a non-money market fund advised by BlackRock or its affiliates (each, a "Non-Money Market BlackRock Fund") as described in the applicable prospectuses. No deferred sales charge is deducted upon the redemption of Investor B or Investor C Shares of the Fund that are purchased from the Trust and not acquired by exchange.

[3] Based on the conversion of Investor B Shares to Investor A Shares after eight years (applies to shares received in an exchange transaction for Investor B Shares of certain equity Non-Money Market BlackRock Funds).

[4] Based on the conversion of Investor B Shares to Investor A Shares after seven years (applies to shares received in an exchange transaction for Investor B Shares of certain fixed-income Non-Money Market BlackRock Funds).

[5] Based on the conversion of Investor B Shares to Investor A Shares after ten years (applies to shares received in an exchange transaction for Investor B Shares of certain fixed-income Non-Money Market BlackRock Funds).

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Service | BLACKROCK VA MUNI MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Virginia Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Virginia Municipal Money Market Portfolio (the “Virginia Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Virginia state income tax, as is consistent with maintaining liquidity and stability of principal.
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 the Virginia Municipal Money Market 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	August 1, 2014
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	Other Expenses are based on estimated amounts for the current fiscal year.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Virginia Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the Commonwealth of Virginia or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Virginia municipal securities”). The Fund normally invests at least 80% of its net assets in Virginia municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Virginia Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. State Specific Risk — The Fund will invest primarily in Virginia municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Virginia municipal securities. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Virginia municipal securities to be subject to state or local income taxation, or the value of Virginia municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Virginia Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. For the periods October 8, 2003 through May 12, 2005, June 28, 2005 through April 23, 2006, May 3, 2006 through June 1, 2006, and March 12, 2012 through June 30, 2013, there were no Service Shares outstanding. For the periods during which Service Shares were not outstanding, the performance of the Service Shares is based on the return of Institutional Shares, adjusted to reflect the expenses of Service Shares. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The information shows you how the Virginia Municipal Money Market Portfolio’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) 537-4942
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Service Shares ANNUAL TOTAL RETURNS Virginia Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.80% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%. Because there were no Service Shares outstanding during the year-to-date ended June 30, 2013, the year-to-date return as of June 30, 2013 is based on the return of Institutional Shares, adjusted to reflect the expenses of Service Shares.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 537-4942.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 537-4942
Service | BLACKROCK VA MUNI MONEY MARKET PORTFOLIO | Service Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%	[1]
Service Fees	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.25%	[1]
Other Expenses	rr_OtherExpensesOverAssets	0.49%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.19%	[1]
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.59%)	[1],[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.60%	[1],[2]
1 Year	rr_ExpenseExampleYear01	$ 61
3 Years	rr_ExpenseExampleYear03	319
5 Years	rr_ExpenseExampleYear05	597
10 Years	rr_ExpenseExampleYear10	$ 1,391
2003	rr_AnnualReturn2003	0.74%
2004	rr_AnnualReturn2004	0.67%
2005	rr_AnnualReturn2005	1.84%
2006	rr_AnnualReturn2006	2.87%
2007	rr_AnnualReturn2007	3.08%
2008	rr_AnnualReturn2008	1.58%
2009	rr_AnnualReturn2009	0.04%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.80%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.32%
10 Years	rr_AverageAnnualReturnYear10	1.08%

[1] Other Expenses are based on estimated amounts for the current fiscal year. There were no Service Shares outstanding at the end of the most recent fiscal year.

[2] As described in the “Management of the Funds” section of the Fund’s prospectus on pages 46-50, BlackRock Advisors, LLC (“BlackRock”) has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.60% of average daily net assets until August 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 Virginia Municipal Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Investor A, Institutional | BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Municipal Money Market Portfolio (the “Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax as is consistent with maintaining liquidity and stability of principal.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Municipal Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Municipal Money Market Portfolio seeks to achieve its investment objective by investing at least 80% of its net assets in short-term obligations issued by or on behalf of states, possessions and territories of the United States, their political subdivisions and their agencies (“municipal securities”) and other instruments whose interest, in the opinion of counsel to the issuer of the municipal security or other instrument, is exempt from regular Federal income tax and the Federal alternative minimum tax. The Fund intends to invest so that less than 25% of its total assets are municipal securities of issuers located in the same state. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on state municipal securities to be subject to state or local income taxation, or the value of state municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting 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 Municipal Money Market Portfolio’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	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Investor A Shares ANNUAL TOTAL RETURNS Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.78% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 441-7762.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 441-7762
Investor A, Institutional | BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.29%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.99%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.10%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.89%	[1]
1 Year	rr_ExpenseExampleYear01	$ 91
3 Years	rr_ExpenseExampleYear03	305
5 Years	rr_ExpenseExampleYear05	537
10 Years	rr_ExpenseExampleYear10	1,204
2003	rr_AnnualReturn2003	0.39%
2004	rr_AnnualReturn2004	0.55%
2005	rr_AnnualReturn2005	1.70%
2006	rr_AnnualReturn2006	2.81%
2007	rr_AnnualReturn2007	3.04%
2008	rr_AnnualReturn2008	1.66%
2009	rr_AnnualReturn2009	0.07%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.01%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.78%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.35%
10 Years	rr_AverageAnnualReturnYear10	1.02%
Investor A, Institutional | BLACKROCK MUNICIPAL MONEY MARKET PORTFOLIO | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.34%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.79%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.37%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.42%	[1]
1 Year	rr_ExpenseExampleYear01	43
3 Years	rr_ExpenseExampleYear03	215
5 Years	rr_ExpenseExampleYear05	402
10 Years	rr_ExpenseExampleYear10	$ 943
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.44%
10 Years	rr_AverageAnnualReturnYear10	1.23%

[1] As described in the “Management of the Funds” section of the Fund’s prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.89% (for Investor A Shares) and 0.42% (for Institutional Shares) until August 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 Municipal Money Market Portfolio.

XML

Service | BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock New Jersey Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock New Jersey Municipal Money Market Portfolio (the “New Jersey Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, New Jersey state income tax, as is consistent with maintaining liquidity and stability of principal.

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 the New Jersey Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses		Service BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO Service Shares
Management Fee		0.45%
Service Fees		0.25%
Other Expenses		0.30%
Total Annual Fund Operating Expenses		1.00%
Fee Waivers and/or Expense Reimbursements	[1]	(0.31%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.69%

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	5 Years	10 Years
Service BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO Service Shares	70	288	522	1,196

Principal Investment Strategies of the Fund

The New Jersey Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of New Jersey or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“New Jersey municipal securities”). The Fund normally invests at least 80% of its net assets in New Jersey municipal securities. In addition, the Fund normally invests at least 80% of its assets in New Jersey municipal securities and other obligations which, in bond counsel’s opinion, are statutorily free from state and local taxation under the laws of New Jersey or the U.S. in order to qualify as a “qualified investment fund” under New Jersey law. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The New Jersey Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• State Specific Risk — The Fund will invest primarily in New Jersey municipal securities. As a result, the Fund is more exposed to risks affecting issuers of New Jersey municipal securities.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on New Jersey municipal securities to be subject to state or local income taxation, or the value of New Jersey municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the New Jersey Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.

Service Shares
ANNUAL TOTAL RETURNS
New Jersey Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.77% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns	1 Year	5 Years	10 Years
Service BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO Service Shares	none	0.36%	1.03%

To obtain the Fund’s current 7-day yield, call (800) 537-4942.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.69% of average daily net assets until August 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 New Jersey Municipal Money Market Portfolio.

XML

Investor A, Institutional | BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO

Fund Overview

Key Facts About BlackRock New Jersey Municipal Money Market Portfolio

Investment Objective

The investment objective of BlackRock New Jersey Municipal Money Market Portfolio (the “New Jersey Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock Funds^SM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, New Jersey state income tax, as is consistent with maintaining liquidity and stability of principal.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the New Jersey Municipal Money Market Portfolio.

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

Annual Fund Operating Expenses Investor A, Institutional BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO		Investor A Shares	Institutional Shares
Management Fee		0.45%	0.45%
Distribution and/or Service (12b-1) Fees		0.25%	none
Other Expenses		0.62%	0.40%
Total Annual Fund Operating Expenses		1.32%	0.85%
Fee Waivers and/or Expense Reimbursements	[1]	(0.36%)	(0.46%)
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	[1]	0.96%	0.39%

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 Investor A, Institutional BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO (USD $)	1 Year	3 Years	5 Years	10 Years
Investor A Shares	98	383	689	1,559
Institutional Shares	40	225	426	1,006

Principal Investment Strategies of the Fund

The New Jersey Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of New Jersey or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“New Jersey municipal securities”). The Fund normally invests at least 80% of its net assets in New Jersey municipal securities. In addition, the Fund normally invests at least 80% of its assets in New Jersey municipal securities and other obligations which, in bond counsel’s opinion, are statutorily free from state and local taxation under the laws of New Jersey or the U.S. in order to qualify as a “qualified investment fund” under New Jersey law. The Fund may also invest in repurchase agreements and purchase and sale contracts.

The Fund seeks to maintain a net asset value of $1.00 per share.

The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).

Principal Risks of Investing in the Fund

The New Jersey Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective.

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund.

• Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

• Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

• 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.
  
  Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

• 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.

• Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance.

• Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities.

• Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.

• Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential.

• 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 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 may lose money.

• State Specific Risk — The Fund will invest primarily in New Jersey municipal securities. As a result, the Fund is more exposed to risks affecting issuers of New Jersey municipal securities.

• Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on New Jersey municipal securities to be subject to state or local income taxation, or the value of New Jersey municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.

Performance Information

The information shows you how the New Jersey Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 882-0052.

Investor A Shares
ANNUAL TOTAL RETURNS
New Jersey Municipal Money Market Portfolio
As of 12/31

During the period shown in the bar chart, the highest return for a quarter was 0.77% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.

As of 12/31/12
Average Annual Total Returns

Average Annual Total Returns Investor A, Institutional BLACKROCK NJ MUNI MONEY MARKET PORTFOLIO	1 Year	5 Years	10 Years
Investor A Shares	none	0.36%	1.02%
Institutional Shares	none	0.47%	1.24%

To obtain the Fund’s current 7-day yield, call (800) 441-7762.

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 53–57, 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 certain other Fund expenses) as a percentage of average daily net assets to 0.96% (for Investor A Shares) and 0.39% (for Institutional Shares) until August 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 New Jersey Municipal Money Market Portfolio.

XML

Document and Entity Information	12 Months Ended
	Jul. 29, 2013
Risk/Return:
Document Type	485BPOS
Document Period End Date	Mar. 31, 2013
Registrant Name	BLACKROCK FUNDS
Central Index Key	0000844779
Amendment Flag	false
Document Creation Date	Jul. 29, 2013
Document Effective Date	Jul. 29, 2013
Prospectus Date	Jul. 29, 2013

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Service | BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock U.S. Treasury Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock U.S. Treasury Money Market Portfolio (the “U.S. Treasury Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income as is consistent with maintaining liquidity and stability of principal.
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 the U.S. Treasury Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The U.S. Treasury Money Market Portfolio seeks to achieve its investment objective by investing 80% of its net assets in short-term bills, notes and other obligations issued or guaranteed by the U.S. Treasury and related repurchase agreements. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The U.S. Treasury Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. Treasury Obligations Risk — Direct obligations of the U.S. Treasury have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. U.S. Government Obligations Risk — Certain securities in which the 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.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the U.S. Treasury Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The information shows you how the U.S. Treasury Money Market Portfolio’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) 537-4942
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Service Shares ANNUAL TOTAL RETURNS U.S. Treasury Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 1.16% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 537-4942.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 537-4942
Service | BLACKROCK U.S. TREASURY MONEY MARKET PORTFOLIO | Service Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Service Fees	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.27%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.97%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.26%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.71%	[1]
1 Year	rr_ExpenseExampleYear01	$ 73
3 Years	rr_ExpenseExampleYear03	283
5 Years	rr_ExpenseExampleYear05	511
10 Years	rr_ExpenseExampleYear10	$ 1,166
2003	rr_AnnualReturn2003	0.48%
2004	rr_AnnualReturn2004	0.62%
2005	rr_AnnualReturn2005	2.47%
2006	rr_AnnualReturn2006	4.36%
2007	rr_AnnualReturn2007	4.34%
2008	rr_AnnualReturn2008	1.20%
2009	rr_AnnualReturn2009	0.01%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2006
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	1.16%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.24%
10 Years	rr_AverageAnnualReturnYear10	1.33%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46-50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.71% of average daily net assets until August 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 U.S. Treasury Money Market Portfolio.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 29, 2013
Service | BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Ohio Municipal Money Market Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Ohio Municipal Money Market Portfolio (the “Ohio Municipal Money Market Portfolio” or the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek as high a level of current income exempt from Federal income tax and, to the extent possible, Ohio state income tax, as is consistent with maintaining liquidity and stability of principal.
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 the Ohio Municipal Money Market 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	August 1, 2014
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Ohio Municipal Money Market Portfolio seeks to achieve its investment objective by investing primarily in high quality, short-term municipal securities issued by or on behalf of the State of Ohio or its agencies, political subdivisions or instrumentalities, or other qualifying issuer, that pay interest that, in the opinion of bond counsel to the issuer, is excludable from gross income for Federal income tax purposes (but may subject investors to Federal alternative minimum tax) and exempt from any applicable state or local income or other taxes (“Ohio municipal securities”). The Fund normally invests at least 80% of its net assets in Ohio municipal securities. The Fund may also invest in repurchase agreements and purchase and sale contracts. The Fund seeks to maintain a net asset value of $1.00 per share. The securities purchased by the Fund are subject to the quality, diversification and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and Exchange Commission (“SEC”).
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Ohio Municipal Money Market Portfolio cannot guarantee that it will achieve its investment objective. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. The following is a summary description of principal risks of investing in the Fund. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. 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. Additionally, securities issued or guaranteed by the U.S. Government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. 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. Municipal Securities Concentration Risk — From time to time, the Fund may invest a substantial amount of its assets in municipal securities whose interest is paid solely from revenues of similar projects. If the Fund concentrates its investments in this manner, it assumes the legal and economic risks relating to such projects and this may have a significant impact on the Fund’s investment performance. Municipal Securities Risk — 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. Certain municipal securities, including private activity bonds, are not backed by the full faith, credit and taxing power of the issuer. Additionally, if events occur after the security is acquired that impact the security’s tax-exempt status, the Fund and its shareholders could be subject to substantial tax liabilities. Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely. Regulatory Risk — In 2010, the SEC adopted amendments to money market fund regulations, which imposed new liquidity, credit quality, and maturity requirements on all money market funds. In addition, in June 2013, the SEC proposed additional reforms to money market fund regulation, which, if adopted, may affect the Fund’s operations and/or return potential. 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 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 may lose money. State Specific Risk — The Fund will invest primarily in Ohio municipal securities. As a result, the Fund is more exposed to risks affecting issuers of Ohio municipal securities. Taxability Risk — Future laws, regulations, rulings or court decisions may cause interest on tax-exempt or municipal securities to be subject, directly or indirectly, to Federal income taxation or interest on Ohio municipal securities to be subject to state or local income taxation, or the value of Ohio municipal securities to be subject to state or local intangible personal property tax, or may otherwise prevent the Fund from realizing the full current benefit of the tax-exempt status of such securities. Any such change could also affect the market price of such securities, and thus the value of an investment in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk — The Fund is a non-diversified fund. Because the Fund may invest in securities of a smaller number of issuers, it may be more exposed to the risks associated with and developments affecting an individual issuer than a fund that invests more widely.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund could lose money if the issuer of an instrument held by the Fund defaults or if short-term interest rates rise sharply in a manner not anticipated by Fund management. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Ohio Municipal Money Market Portfolio’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. 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. The Fund is a money market fund managed pursuant to the requirements of Rule 2a-7 under the Investment Company Act. Effective May 28, 2010, Rule 2a-7 was amended to impose new liquidity, credit quality and maturity requirements on all money market funds. Fund performance shown prior to May 28, 2010 is based on Investment Company Act rules then in effect and is not an indication of future returns. Updated information on the Fund’s results can be obtained by visiting www.blackrock.com/funds or can be obtained by phone at (800) 537-4942.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The information shows you how the Ohio Municipal Money Market Portfolio’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) 537-4942
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.blackrock.com/funds
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Service Shares ANNUAL TOTAL RETURNS Ohio Municipal Money Market Portfolio As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the period shown in the bar chart, the highest return for a quarter was 0.80% (quarter ended June 30, 2007) and the lowest return for a quarter was 0.00% (quarter ended December 31, 2012). The year-to-date return as of June 30, 2013 was 0.00%.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/12 Average Annual Total Returns
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	The table includes all applicable fees and sales charges.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	To obtain the Fund’s current 7-day yield, call (800) 537-4942.
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	(800) 537-4942
Service | BLACKROCK OHIO MUNI MONEY MARKET PORTFOLIO | Service Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.45%
Service Fees	rr_DistributionOrSimilarNon12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.34%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.04%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.35%)	[1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.69%	[1]
1 Year	rr_ExpenseExampleYear01	$ 70
3 Years	rr_ExpenseExampleYear03	296
5 Years	rr_ExpenseExampleYear05	540
10 Years	rr_ExpenseExampleYear10	$ 1,239
2003	rr_AnnualReturn2003	0.63%
2004	rr_AnnualReturn2004	0.69%
2005	rr_AnnualReturn2005	1.85%
2006	rr_AnnualReturn2006	2.89%
2007	rr_AnnualReturn2007	3.10%
2008	rr_AnnualReturn2008	1.91%
2009	rr_AnnualReturn2009	0.20%
2010	rr_AnnualReturn2010	0.00%
2011	rr_AnnualReturn2011	0.00%
2012	rr_AnnualReturn2012	0.00%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.80%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1 Year	rr_AverageAnnualReturnYear01	none
5 Years	rr_AverageAnnualReturnYear05	0.42%
10 Years	rr_AverageAnnualReturnYear10	1.12%

[1] As described in the "Management of the Funds" section of the Fund's prospectus on pages 46–50, BlackRock Advisors, LLC ("BlackRock") has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Service Shares 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 0.69% of average daily net assets until August 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 Ohio Municipal Money Market Portfolio.