v3.26.3
Investor A C Institutional And Class R [Member] Expense Example - Investor A, C, Institutional and Class R - BLACKROCK MID CAP GROWTH EQUITY PORTFOLIO
May 31, 2026
USD ($)
INSTITUTIONAL  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 82
Expense Example, with Redemption, 3 Years 268
Expense Example, with Redemption, 5 Years 471
Expense Example, with Redemption, 10 Years 1,055
INVESTOR A  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 626
Expense Example, with Redemption, 3 Years 856
Expense Example, with Redemption, 5 Years 1,103
Expense Example, with Redemption, 10 Years 1,811
INVESTOR C  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 283
Expense Example, with Redemption, 3 Years 575
Expense Example, with Redemption, 5 Years 992
Expense Example, with Redemption, 10 Years 1,967
Class R Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 132
Expense Example, with Redemption, 3 Years 440
Expense Example, with Redemption, 5 Years 769
Expense Example, with Redemption, 10 Years $ 1,702