Service Shares [Member] Expense Example - Service Shares [Member] - BLACKROCK HEALTH SCIENCES OPPORTUNITIES PORTFOLIO - SERVICE	May 31, 2025 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 117
Expense Example, with Redemption, 3 Years	365
Expense Example, with Redemption, 5 Years	633
Expense Example, with Redemption, 10 Years	$ 1,398

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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