Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Dec. 29, 2017
Supplement [Text Block]	bf1_SupplementTextBlock	BLACKROCK FUNDS^SM BlackRock Multi-Manager Alternative Strategies Fund (the “Fund”) Supplement dated March 15, 2018 to the Summary Prospectus, Prospectus and Statement of Additional Information of the Fund, each dated December 29, 2017 BlackRock Advisors, LLC, the Fund’s investment adviser (“BlackRock”), determined to terminate the sub-advisory agreement between BlackRock and Pine River Capital Management L.P. (“Pine River”). As a result, pursuant to the terms of such agreement, it was terminated effective March 6, 2018. In connection with the termination of the sub-advisory agreement, effective March 6, 2018, all references in the Fund’s Summary Prospectus, Prospectus and Statement of Additional Information to Pine River are hereby deleted in their entirety.
BlackRock Multi-Manager Alternative Strategies Fund
Risk/Return:	rr_RiskReturnAbstract
Supplement [Text Block]	bf1_SupplementTextBlock	BLACKROCK FUNDS^SM BlackRock Multi-Manager Alternative Strategies Fund (the “Fund”) Supplement dated March 15, 2018 to the Summary Prospectus, Prospectus and Statement of Additional Information of the Fund, each dated December 29, 2017 BlackRock Advisors, LLC, the Fund’s investment adviser (“BlackRock”), determined to terminate the sub-advisory agreement between BlackRock and Pine River Capital Management L.P. (“Pine River”). As a result, pursuant to the terms of such agreement, it was terminated effective March 6, 2018. In connection with the termination of the sub-advisory agreement, effective March 6, 2018, all references in the Fund’s Summary Prospectus, Prospectus and Statement of Additional Information to Pine River are hereby deleted in their entirety.

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

BLACKROCK FUNDS

Prospectus Date

rr_ProspectusDate

Dec. 29, 2017

Supplement [Text Block]

bf1_SupplementTextBlock

BLACKROCK FUNDS^SM

BlackRock Multi-Manager Alternative Strategies Fund

(the “Fund”)

Supplement dated March 15, 2018 to the Summary Prospectus, Prospectus and Statement of Additional Information of the Fund, each dated December 29, 2017

BlackRock Advisors, LLC, the Fund’s investment adviser (“BlackRock”), determined to terminate the sub-advisory agreement between BlackRock and Pine River Capital Management L.P. (“Pine River”). As a result, pursuant to the terms of such agreement, it was terminated effective March 6, 2018.

In connection with the termination of the sub-advisory agreement, effective March 6, 2018, all references in the Fund’s Summary Prospectus, Prospectus and Statement of Additional Information to Pine River are hereby deleted in their entirety.

BlackRock Multi-Manager Alternative Strategies Fund