v3.26.1
Investor A C And Institutional [Member] Investment Objectives and Goals - Investor A, C and Institutional - BlackRock Systematic Multi-Strategy Fund
Dec. 31, 2025
Prospectus [Line Items]  
Risk/Return [Heading] Fund OverviewKey Facts About BlackRock Systematic Multi-Strategy Fund
Objective [Heading] Investment Objective
Objective, Primary [Text Block]
The investment objective of BlackRock Systematic Multi-Strategy Fund (the “Fund”), a series of BlackRock Funds IV (the Trust), is to seek total return comprised of current income and capital appreciation.