v3.26.1
Shareholder Report
 6 Months Ended
Apr. 30, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name BlackRock Funds III
Entity Central Index Key 0000893818
Entity Investment Company Type N-1A
Document Period End Date Apr. 30, 2026
C000220929 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index Retirement Fund
Class Name Class K Shares
Trading Symbol LERKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index Retirement Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $3(a) 0.05%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 3 [1]
Expense Ratio, Percent 0.05% [1],[2]
Net Assets $ 13,979,060
Holdings Count | Holding 12
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $13,979,060
Number of Portfolio Holdings 12
Portfolio Turnover Rate 18%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Fixed-Income Funds 59.1 %
Equity Funds 40.7 %
Money Market Funds 18.9 %
Liabilities in Excess of Other Assets (18.7 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 51.5 %
iShares ESG Aware MSCI USA ETF 21.2 %
iShares ESG Aware MSCI EAFE ETF 7.6 %
iShares TIPS Bond ETF 7.6 %
iShares ESG Aware MSCI EM ETF 4.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 2.6 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.3 %
iShares MSCI Canada ETF 1.1 %
iShares MSCI Emerging Markets Small-Cap ETF 0.6 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 51.5 %
iShares ESG Aware MSCI USA ETF 21.2 %
iShares ESG Aware MSCI EAFE ETF 7.6 %
iShares TIPS Bond ETF 7.6 %
iShares ESG Aware MSCI EM ETF 4.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 2.6 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.3 %
iShares MSCI Canada ETF 1.1 %
iShares MSCI Emerging Markets Small-Cap ETF 0.6 %
​(a)
Excludes short-term securities.
C000220931 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index Retirement Fund
Class Name Investor A Shares
Trading Symbol LERAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index Retirement Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $18(a) 0.35%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 18 [3]
Expense Ratio, Percent 0.35% [3],[4]
Net Assets $ 13,979,060
Holdings Count | Holding 12
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $13,979,060
Number of Portfolio Holdings 12
Portfolio Turnover Rate 18%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Fixed-Income Funds 59.1 %
Equity Funds 40.7 %
Money Market Funds 18.9 %
Liabilities in Excess of Other Assets (18.7 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 51.5 %
iShares ESG Aware MSCI USA ETF 21.2 %
iShares ESG Aware MSCI EAFE ETF 7.6 %
iShares TIPS Bond ETF 7.6 %
iShares ESG Aware MSCI EM ETF 4.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 2.6 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.3 %
iShares MSCI Canada ETF 1.1 %
iShares MSCI Emerging Markets Small-Cap ETF 0.6 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 51.5 %
iShares ESG Aware MSCI USA ETF 21.2 %
iShares ESG Aware MSCI EAFE ETF 7.6 %
iShares TIPS Bond ETF 7.6 %
iShares ESG Aware MSCI EM ETF 4.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 2.6 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.3 %
iShares MSCI Canada ETF 1.1 %
iShares MSCI Emerging Markets Small-Cap ETF 0.6 %
​(a)
Excludes short-term securities.
C000220930 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index Retirement Fund
Class Name Institutional Shares
Trading Symbol LERIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index Retirement Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $5(a) 0.10%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 5 [5]
Expense Ratio, Percent 0.10% [5],[6]
Net Assets $ 13,979,060
Holdings Count | Holding 12
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $13,979,060
Number of Portfolio Holdings 12
Portfolio Turnover Rate 18%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Fixed-Income Funds 59.1 %
Equity Funds 40.7 %
Money Market Funds 18.9 %
Liabilities in Excess of Other Assets (18.7 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 51.5 %
iShares ESG Aware MSCI USA ETF 21.2 %
iShares ESG Aware MSCI EAFE ETF 7.6 %
iShares TIPS Bond ETF 7.6 %
iShares ESG Aware MSCI EM ETF 4.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 2.6 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.3 %
iShares MSCI Canada ETF 1.1 %
iShares MSCI Emerging Markets Small-Cap ETF 0.6 %

​(a)

Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 51.5 %
iShares ESG Aware MSCI USA ETF 21.2 %
iShares ESG Aware MSCI EAFE ETF 7.6 %
iShares TIPS Bond ETF 7.6 %
iShares ESG Aware MSCI EM ETF 4.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 2.6 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.3 %
iShares MSCI Canada ETF 1.1 %
iShares MSCI Emerging Markets Small-Cap ETF 0.6 %

​(a)

Excludes short-term securities.
C000220934 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2065 Fund
Class Name Institutional Shares
Trading Symbol LEWIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2065 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $3(a) 0.05%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 3 [7]
Expense Ratio, Percent 0.05% [7],[8]
Net Assets $ 8,870,396
Holdings Count | Holding 11
Investment Company Portfolio Turnover 7.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $8,870,396
Number of Portfolio Holdings 11
Portfolio Turnover Rate 7%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 98.9 %
Money Market Funds 38.3 %
Fixed-Income Funds 1.0 %
Liabilities in Excess of Other Assets (38.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.0 %
iShares ESG Aware MSCI EM ETF 10.7 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.0 %
iShares ESG Aware MSCI EM ETF 10.7 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
C000220932 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2065 Fund
Class Name Investor A Shares
Trading Symbol LEWAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2065 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $16(a) 0.30%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 16 [9]
Expense Ratio, Percent 0.30% [9],[10]
Net Assets $ 8,870,396
Holdings Count | Holding 11
Investment Company Portfolio Turnover 7.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $8,870,396
Number of Portfolio Holdings 11
Portfolio Turnover Rate 7%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 98.9 %
Money Market Funds 38.3 %
Fixed-Income Funds 1.0 %
Liabilities in Excess of Other Assets (38.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.0 %
iShares ESG Aware MSCI EM ETF 10.7 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.0 %
iShares ESG Aware MSCI EM ETF 10.7 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
C000220933 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2065 Fund
Class Name Class K Shares
Trading Symbol LEWKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2065 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $0(a)(b) 0.00%(a)(c)(d)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Rounds to less than $1.
​(c)
Annualized.
​(d)
Rounds to less than 0.01%.
Expenses Paid, Amount $ 0 [11],[12]
Expense Ratio, Percent 0.00% [11],[13],[14]
Net Assets $ 8,870,396
Holdings Count | Holding 11
Investment Company Portfolio Turnover 7.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $8,870,396
Number of Portfolio Holdings 11
Portfolio Turnover Rate 7%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 98.9 %
Money Market Funds 38.3 %
Fixed-Income Funds 1.0 %
Liabilities in Excess of Other Assets (38.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.0 %
iShares ESG Aware MSCI EM ETF 10.7 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.0 %
iShares ESG Aware MSCI EM ETF 10.7 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
C000220940 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2030 Fund
Class Name Class K Shares
Trading Symbol LENKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2030 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $2(a) 0.04%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 2 [15]
Expense Ratio, Percent 0.04% [15],[16]
Net Assets $ 17,158,052
Holdings Count | Holding 12
Investment Company Portfolio Turnover 10.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $17,158,052
Number of Portfolio Holdings 12
Portfolio Turnover Rate 10%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 50.9 %
Fixed-Income Funds 48.9 %
Money Market Funds 17.4 %
Liabilities in Excess of Other Assets (17.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 41.9 %
iShares ESG Aware MSCI USA ETF 26.5 %
iShares ESG Aware MSCI EAFE ETF 9.8 %
iShares TIPS Bond ETF 7.1 %
iShares ESG Aware MSCI EM ETF 5.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.2 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.6 %
iShares MSCI Canada ETF 1.4 %
iShares MSCI Emerging Markets Small-Cap ETF 0.8 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 41.9 %
iShares ESG Aware MSCI USA ETF 26.5 %
iShares ESG Aware MSCI EAFE ETF 9.8 %
iShares TIPS Bond ETF 7.1 %
iShares ESG Aware MSCI EM ETF 5.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.2 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.6 %
iShares MSCI Canada ETF 1.4 %
iShares MSCI Emerging Markets Small-Cap ETF 0.8 %
​(a)
Excludes short-term securities.
C000220939 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2030 Fund
Class Name Investor A Shares
Trading Symbol LENAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2030 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $17(a) 0.34%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 17 [17]
Expense Ratio, Percent 0.34% [17],[18]
Net Assets $ 17,158,052
Holdings Count | Holding 12
Investment Company Portfolio Turnover 10.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $17,158,052
Number of Portfolio Holdings 12
Portfolio Turnover Rate 10%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 50.9 %
Fixed-Income Funds 48.9 %
Money Market Funds 17.4 %
Liabilities in Excess of Other Assets (17.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 41.9 %
iShares ESG Aware MSCI USA ETF 26.5 %
iShares ESG Aware MSCI EAFE ETF 9.8 %
iShares TIPS Bond ETF 7.1 %
iShares ESG Aware MSCI EM ETF 5.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.2 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.6 %
iShares MSCI Canada ETF 1.4 %
iShares MSCI Emerging Markets Small-Cap ETF 0.8 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 41.9 %
iShares ESG Aware MSCI USA ETF 26.5 %
iShares ESG Aware MSCI EAFE ETF 9.8 %
iShares TIPS Bond ETF 7.1 %
iShares ESG Aware MSCI EM ETF 5.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.2 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.6 %
iShares MSCI Canada ETF 1.4 %
iShares MSCI Emerging Markets Small-Cap ETF 0.8 %
​(a)
Excludes short-term securities.
C000220938 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2030 Fund
Class Name Institutional Shares
Trading Symbol LENIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2030 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $5(a) 0.09%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 5 [19]
Expense Ratio, Percent 0.09% [19],[20]
Net Assets $ 17,158,052
Holdings Count | Holding 12
Investment Company Portfolio Turnover 10.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $17,158,052
Number of Portfolio Holdings 12
Portfolio Turnover Rate 10%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 50.9 %
Fixed-Income Funds 48.9 %
Money Market Funds 17.4 %
Liabilities in Excess of Other Assets (17.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 41.9 %
iShares ESG Aware MSCI USA ETF 26.5 %
iShares ESG Aware MSCI EAFE ETF 9.8 %
iShares TIPS Bond ETF 7.1 %
iShares ESG Aware MSCI EM ETF 5.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.2 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.6 %
iShares MSCI Canada ETF 1.4 %
iShares MSCI Emerging Markets Small-Cap ETF 0.8 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware U.S. Aggregate Bond ETF 41.9 %
iShares ESG Aware MSCI USA ETF 26.5 %
iShares ESG Aware MSCI EAFE ETF 9.8 %
iShares TIPS Bond ETF 7.1 %
iShares ESG Aware MSCI EM ETF 5.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.2 %
iShares Developed Real Estate Index Fund, Class K 2.3 %
iShares MSCI EAFE Small-Cap ETF 1.6 %
iShares MSCI Canada ETF 1.4 %
iShares MSCI Emerging Markets Small-Cap ETF 0.8 %
​(a)
Excludes short-term securities.
C000220941 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2035 Fund
Class Name Institutional Shares
Trading Symbol LEJIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2035 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $4(a) 0.08%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 4 [21]
Expense Ratio, Percent 0.08% [21],[22]
Net Assets $ 16,943,994
Holdings Count | Holding 12
Investment Company Portfolio Turnover 10.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $16,943,994
Number of Portfolio Holdings 12
Portfolio Turnover Rate 10%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 62.8 %
Fixed-Income Funds 37.0 %
Money Market Funds 31.1 %
Liabilities in Excess of Other Assets (30.9 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 32.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 30.8 %
iShares ESG Aware MSCI EAFE ETF 12.2 %
iShares ESG Aware MSCI EM ETF 6.6 %
iShares TIPS Bond ETF 6.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.9 %
iShares Developed Real Estate Index Fund, Class K 2.9 %
iShares MSCI EAFE Small-Cap ETF 2.0 %
iShares MSCI Canada ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.0 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 32.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 30.8 %
iShares ESG Aware MSCI EAFE ETF 12.2 %
iShares ESG Aware MSCI EM ETF 6.6 %
iShares TIPS Bond ETF 6.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.9 %
iShares Developed Real Estate Index Fund, Class K 2.9 %
iShares MSCI EAFE Small-Cap ETF 2.0 %
iShares MSCI Canada ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.0 %
​(a)
Excludes short-term securities.
C000220942 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2035 Fund
Class Name Investor A Shares
Trading Symbol LEJAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2035 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $17(a) 0.33%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 17 [23]
Expense Ratio, Percent 0.33% [23],[24]
Net Assets $ 16,943,994
Holdings Count | Holding 12
Investment Company Portfolio Turnover 10.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $16,943,994
Number of Portfolio Holdings 12
Portfolio Turnover Rate 10%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 62.8 %
Fixed-Income Funds 37.0 %
Money Market Funds 31.1 %
Liabilities in Excess of Other Assets (30.9 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 32.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 30.8 %
iShares ESG Aware MSCI EAFE ETF 12.2 %
iShares ESG Aware MSCI EM ETF 6.6 %
iShares TIPS Bond ETF 6.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.9 %
iShares Developed Real Estate Index Fund, Class K 2.9 %
iShares MSCI EAFE Small-Cap ETF 2.0 %
iShares MSCI Canada ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.0 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 32.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 30.8 %
iShares ESG Aware MSCI EAFE ETF 12.2 %
iShares ESG Aware MSCI EM ETF 6.6 %
iShares TIPS Bond ETF 6.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.9 %
iShares Developed Real Estate Index Fund, Class K 2.9 %
iShares MSCI EAFE Small-Cap ETF 2.0 %
iShares MSCI Canada ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.0 %
​(a)
Excludes short-term securities.
C000220943 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2035 Fund
Class Name Class K Shares
Trading Symbol LEJKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2035 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $2(a) 0.03%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 2 [25]
Expense Ratio, Percent 0.03% [25],[26]
Net Assets $ 16,943,994
Holdings Count | Holding 12
Investment Company Portfolio Turnover 10.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $16,943,994
Number of Portfolio Holdings 12
Portfolio Turnover Rate 10%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 62.8 %
Fixed-Income Funds 37.0 %
Money Market Funds 31.1 %
Liabilities in Excess of Other Assets (30.9 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 32.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 30.8 %
iShares ESG Aware MSCI EAFE ETF 12.2 %
iShares ESG Aware MSCI EM ETF 6.6 %
iShares TIPS Bond ETF 6.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.9 %
iShares Developed Real Estate Index Fund, Class K 2.9 %
iShares MSCI EAFE Small-Cap ETF 2.0 %
iShares MSCI Canada ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.0 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 32.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 30.8 %
iShares ESG Aware MSCI EAFE ETF 12.2 %
iShares ESG Aware MSCI EM ETF 6.6 %
iShares TIPS Bond ETF 6.2 %
iShares ESG Aware MSCI USA Small-Cap ETF 3.9 %
iShares Developed Real Estate Index Fund, Class K 2.9 %
iShares MSCI EAFE Small-Cap ETF 2.0 %
iShares MSCI Canada ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.0 %
​(a)
Excludes short-term securities.
C000220945 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2040 Fund
Class Name Class K Shares
Trading Symbol LEKKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2040 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $1(a) 0.02%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 1 [27]
Expense Ratio, Percent 0.02% [27],[28]
Net Assets $ 28,175,319
Holdings Count | Holding 12
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $28,175,319
Number of Portfolio Holdings 12
Portfolio Turnover Rate 8%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 74.5 %
Fixed-Income Funds 25.3 %
Money Market Funds 18.3 %
Liabilities in Excess of Other Assets (18.1 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 38.2 %
iShares ESG Aware U.S. Aggregate Bond ETF 20.5 %
iShares ESG Aware MSCI EAFE ETF 14.7 %
iShares ESG Aware MSCI EM ETF 8.0 %
iShares TIPS Bond ETF 4.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 4.6 %
iShares Developed Real Estate Index Fund, Class K 3.4 %
iShares MSCI EAFE Small-Cap ETF 2.4 %
iShares MSCI Canada ETF 2.0 %
iShares MSCI Emerging Markets Small-Cap ETF 1.2 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 38.2 %
iShares ESG Aware U.S. Aggregate Bond ETF 20.5 %
iShares ESG Aware MSCI EAFE ETF 14.7 %
iShares ESG Aware MSCI EM ETF 8.0 %
iShares TIPS Bond ETF 4.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 4.6 %
iShares Developed Real Estate Index Fund, Class K 3.4 %
iShares MSCI EAFE Small-Cap ETF 2.4 %
iShares MSCI Canada ETF 2.0 %
iShares MSCI Emerging Markets Small-Cap ETF 1.2 %
​(a)
Excludes short-term securities.
C000220946 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2040 Fund
Class Name Investor A Shares
Trading Symbol LEKAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2040 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $16(a) 0.32%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 16 [29]
Expense Ratio, Percent 0.32% [29],[30]
Net Assets $ 28,175,319
Holdings Count | Holding 12
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $28,175,319
Number of Portfolio Holdings 12
Portfolio Turnover Rate 8%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 74.5 %
Fixed-Income Funds 25.3 %
Money Market Funds 18.3 %
Liabilities in Excess of Other Assets (18.1 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 38.2 %
iShares ESG Aware U.S. Aggregate Bond ETF 20.5 %
iShares ESG Aware MSCI EAFE ETF 14.7 %
iShares ESG Aware MSCI EM ETF 8.0 %
iShares TIPS Bond ETF 4.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 4.6 %
iShares Developed Real Estate Index Fund, Class K 3.4 %
iShares MSCI EAFE Small-Cap ETF 2.4 %
iShares MSCI Canada ETF 2.0 %
iShares MSCI Emerging Markets Small-Cap ETF 1.2 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 38.2 %
iShares ESG Aware U.S. Aggregate Bond ETF 20.5 %
iShares ESG Aware MSCI EAFE ETF 14.7 %
iShares ESG Aware MSCI EM ETF 8.0 %
iShares TIPS Bond ETF 4.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 4.6 %
iShares Developed Real Estate Index Fund, Class K 3.4 %
iShares MSCI EAFE Small-Cap ETF 2.4 %
iShares MSCI Canada ETF 2.0 %
iShares MSCI Emerging Markets Small-Cap ETF 1.2 %
​(a)
Excludes short-term securities.
C000220944 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2040 Fund
Class Name Institutional Shares
Trading Symbol LEKIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2040 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $4(a) 0.07%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 4 [31]
Expense Ratio, Percent 0.07% [31],[32]
Net Assets $ 28,175,319
Holdings Count | Holding 12
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $28,175,319
Number of Portfolio Holdings 12
Portfolio Turnover Rate 8%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 74.5 %
Fixed-Income Funds 25.3 %
Money Market Funds 18.3 %
Liabilities in Excess of Other Assets (18.1 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 38.2 %
iShares ESG Aware U.S. Aggregate Bond ETF 20.5 %
iShares ESG Aware MSCI EAFE ETF 14.7 %
iShares ESG Aware MSCI EM ETF 8.0 %
iShares TIPS Bond ETF 4.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 4.6 %
iShares Developed Real Estate Index Fund, Class K 3.4 %
iShares MSCI EAFE Small-Cap ETF 2.4 %
iShares MSCI Canada ETF 2.0 %
iShares MSCI Emerging Markets Small-Cap ETF 1.2 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 38.2 %
iShares ESG Aware U.S. Aggregate Bond ETF 20.5 %
iShares ESG Aware MSCI EAFE ETF 14.7 %
iShares ESG Aware MSCI EM ETF 8.0 %
iShares TIPS Bond ETF 4.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 4.6 %
iShares Developed Real Estate Index Fund, Class K 3.4 %
iShares MSCI EAFE Small-Cap ETF 2.4 %
iShares MSCI Canada ETF 2.0 %
iShares MSCI Emerging Markets Small-Cap ETF 1.2 %
​(a)
Excludes short-term securities.
C000220948 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2045 Fund
Class Name Institutional Shares
Trading Symbol LEHIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2045 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $3(a) 0.06%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 3 [33]
Expense Ratio, Percent 0.06% [33],[34]
Net Assets $ 24,106,800
Holdings Count | Holding 12
Investment Company Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $24,106,800
Number of Portfolio Holdings 12
Portfolio Turnover Rate 9%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 84.9 %
Money Market Funds 25.4 %
Fixed-Income Funds 14.9 %
Liabilities in Excess of Other Assets (25.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 43.5 %
iShares ESG Aware MSCI EAFE ETF 16.9 %
iShares ESG Aware U.S. Aggregate Bond ETF 11.6 %
iShares ESG Aware MSCI EM ETF 9.1 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.1 %
iShares Developed Real Estate Index Fund, Class K 3.9 %
iShares TIPS Bond ETF 3.3 %
iShares MSCI EAFE Small-Cap ETF 2.7 %
iShares MSCI Canada ETF 2.3 %
iShares MSCI Emerging Markets Small-Cap ETF 1.4 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 43.5 %
iShares ESG Aware MSCI EAFE ETF 16.9 %
iShares ESG Aware U.S. Aggregate Bond ETF 11.6 %
iShares ESG Aware MSCI EM ETF 9.1 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.1 %
iShares Developed Real Estate Index Fund, Class K 3.9 %
iShares TIPS Bond ETF 3.3 %
iShares MSCI EAFE Small-Cap ETF 2.7 %
iShares MSCI Canada ETF 2.3 %
iShares MSCI Emerging Markets Small-Cap ETF 1.4 %
​(a)
Excludes short-term securities.
C000220947 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2045 Fund
Class Name Investor A Shares
Trading Symbol LEHAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2045 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $16(a) 0.31%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 16 [35]
Expense Ratio, Percent 0.31% [35],[36]
Net Assets $ 24,106,800
Holdings Count | Holding 12
Investment Company Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $24,106,800
Number of Portfolio Holdings 12
Portfolio Turnover Rate 9%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 84.9 %
Money Market Funds 25.4 %
Fixed-Income Funds 14.9 %
Liabilities in Excess of Other Assets (25.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 43.5 %
iShares ESG Aware MSCI EAFE ETF 16.9 %
iShares ESG Aware U.S. Aggregate Bond ETF 11.6 %
iShares ESG Aware MSCI EM ETF 9.1 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.1 %
iShares Developed Real Estate Index Fund, Class K 3.9 %
iShares TIPS Bond ETF 3.3 %
iShares MSCI EAFE Small-Cap ETF 2.7 %
iShares MSCI Canada ETF 2.3 %
iShares MSCI Emerging Markets Small-Cap ETF 1.4 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 43.5 %
iShares ESG Aware MSCI EAFE ETF 16.9 %
iShares ESG Aware U.S. Aggregate Bond ETF 11.6 %
iShares ESG Aware MSCI EM ETF 9.1 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.1 %
iShares Developed Real Estate Index Fund, Class K 3.9 %
iShares TIPS Bond ETF 3.3 %
iShares MSCI EAFE Small-Cap ETF 2.7 %
iShares MSCI Canada ETF 2.3 %
iShares MSCI Emerging Markets Small-Cap ETF 1.4 %
​(a)
Excludes short-term securities.
C000220949 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2045 Fund
Class Name Class K Shares
Trading Symbol LEHKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2045 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $1(a) 0.01%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 1 [37]
Expense Ratio, Percent 0.01% [37],[38]
Net Assets $ 24,106,800
Holdings Count | Holding 12
Investment Company Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $24,106,800
Number of Portfolio Holdings 12
Portfolio Turnover Rate 9%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 84.9 %
Money Market Funds 25.4 %
Fixed-Income Funds 14.9 %
Liabilities in Excess of Other Assets (25.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 43.5 %
iShares ESG Aware MSCI EAFE ETF 16.9 %
iShares ESG Aware U.S. Aggregate Bond ETF 11.6 %
iShares ESG Aware MSCI EM ETF 9.1 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.1 %
iShares Developed Real Estate Index Fund, Class K 3.9 %
iShares TIPS Bond ETF 3.3 %
iShares MSCI EAFE Small-Cap ETF 2.7 %
iShares MSCI Canada ETF 2.3 %
iShares MSCI Emerging Markets Small-Cap ETF 1.4 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 43.5 %
iShares ESG Aware MSCI EAFE ETF 16.9 %
iShares ESG Aware U.S. Aggregate Bond ETF 11.6 %
iShares ESG Aware MSCI EM ETF 9.1 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.1 %
iShares Developed Real Estate Index Fund, Class K 3.9 %
iShares TIPS Bond ETF 3.3 %
iShares MSCI EAFE Small-Cap ETF 2.7 %
iShares MSCI Canada ETF 2.3 %
iShares MSCI Emerging Markets Small-Cap ETF 1.4 %
​(a)
Excludes short-term securities.
C000220952 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2050 Fund
Class Name Class K Shares
Trading Symbol LEPKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2050 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $0(a)(b) 0.00%(a)(c)(d)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Rounds to less than $1.
​(c)
Annualized.
​(d)
Rounds to less than 0.01%.
Expenses Paid, Amount $ 0 [39],[40]
Expense Ratio, Percent 0.00% [39],[41],[42]
Net Assets $ 26,402,877
Holdings Count | Holding 12
Investment Company Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $26,402,877
Number of Portfolio Holdings 12
Portfolio Turnover Rate 9%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 93.4 %
Money Market Funds 25.3 %
Fixed-Income Funds 6.5 %
Liabilities in Excess of Other Assets (25.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 47.8 %
iShares ESG Aware MSCI EAFE ETF 18.8 %
iShares ESG Aware MSCI EM ETF 10.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 4.7 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.1 %
iShares MSCI Canada ETF 2.5 %
iShares TIPS Bond ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 47.8 %
iShares ESG Aware MSCI EAFE ETF 18.8 %
iShares ESG Aware MSCI EM ETF 10.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 4.7 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.1 %
iShares MSCI Canada ETF 2.5 %
iShares TIPS Bond ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
​(a)
Excludes short-term securities.
C000220950 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2050 Fund
Class Name Investor A Shares
Trading Symbol LEBAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2050 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $15(a) 0.30%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 15 [43]
Expense Ratio, Percent 0.30% [43],[44]
Net Assets $ 26,402,877
Holdings Count | Holding 12
Investment Company Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $26,402,877
Number of Portfolio Holdings 12
Portfolio Turnover Rate 9%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 93.4 %
Money Market Funds 25.3 %
Fixed-Income Funds 6.5 %
Liabilities in Excess of Other Assets (25.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 47.8 %
iShares ESG Aware MSCI EAFE ETF 18.8 %
iShares ESG Aware MSCI EM ETF 10.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 4.7 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.1 %
iShares MSCI Canada ETF 2.5 %
iShares TIPS Bond ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 47.8 %
iShares ESG Aware MSCI EAFE ETF 18.8 %
iShares ESG Aware MSCI EM ETF 10.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 4.7 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.1 %
iShares MSCI Canada ETF 2.5 %
iShares TIPS Bond ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
​(a)
Excludes short-term securities.
C000220951 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2050 Fund
Class Name Institutional Shares
Trading Symbol LEGIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2050 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $3(a) 0.05%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 3 [45]
Expense Ratio, Percent 0.05% [45],[46]
Net Assets $ 26,402,877
Holdings Count | Holding 12
Investment Company Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $26,402,877
Number of Portfolio Holdings 12
Portfolio Turnover Rate 9%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 93.4 %
Money Market Funds 25.3 %
Fixed-Income Funds 6.5 %
Liabilities in Excess of Other Assets (25.2 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 47.8 %
iShares ESG Aware MSCI EAFE ETF 18.8 %
iShares ESG Aware MSCI EM ETF 10.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 4.7 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.1 %
iShares MSCI Canada ETF 2.5 %
iShares TIPS Bond ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 47.8 %
iShares ESG Aware MSCI EAFE ETF 18.8 %
iShares ESG Aware MSCI EM ETF 10.0 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 4.7 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.1 %
iShares MSCI Canada ETF 2.5 %
iShares TIPS Bond ETF 1.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
​(a)
Excludes short-term securities.
C000220955 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2055 Fund
Class Name Institutional Shares
Trading Symbol LEEIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2055 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $3(a) 0.05%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 3 [47]
Expense Ratio, Percent 0.05% [47],[48]
Net Assets $ 20,247,241
Holdings Count | Holding 12
Investment Company Portfolio Turnover 6.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $20,247,241
Number of Portfolio Holdings 12
Portfolio Turnover Rate 6%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 97.8 %
Money Market Funds 33.8 %
Fixed-Income Funds 2.0 %
Liabilities in Excess of Other Assets (33.6 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.1 %
iShares ESG Aware MSCI EAFE ETF 19.8 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.8 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.4 %
iShares TIPS Bond ETF 0.5 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.1 %
iShares ESG Aware MSCI EAFE ETF 19.8 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.8 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.4 %
iShares TIPS Bond ETF 0.5 %
​(a)
Excludes short-term securities.
C000220953 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2055 Fund
Class Name Investor A Shares
Trading Symbol LEVAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2055 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $16(a) 0.30%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 16 [49]
Expense Ratio, Percent 0.30% [49],[50]
Net Assets $ 20,247,241
Holdings Count | Holding 12
Investment Company Portfolio Turnover 6.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $20,247,241
Number of Portfolio Holdings 12
Portfolio Turnover Rate 6%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 97.8 %
Money Market Funds 33.8 %
Fixed-Income Funds 2.0 %
Liabilities in Excess of Other Assets (33.6 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.1 %
iShares ESG Aware MSCI EAFE ETF 19.8 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.8 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.4 %
iShares TIPS Bond ETF 0.5 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.1 %
iShares ESG Aware MSCI EAFE ETF 19.8 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.8 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.4 %
iShares TIPS Bond ETF 0.5 %
​(a)
Excludes short-term securities.
C000220954 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2055 Fund
Class Name Class K Shares
Trading Symbol LEVKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2055 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $0(a)(b) 0.00%(a)(c)(d)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Rounds to less than $1.
​(c)
Annualized.
​(d)
Rounds to less than 0.01%.
Expenses Paid, Amount $ 0 [51],[52]
Expense Ratio, Percent 0.00% [51],[53],[54]
Net Assets $ 20,247,241
Holdings Count | Holding 12
Investment Company Portfolio Turnover 6.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $20,247,241
Number of Portfolio Holdings 12
Portfolio Turnover Rate 6%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 97.8 %
Money Market Funds 33.8 %
Fixed-Income Funds 2.0 %
Liabilities in Excess of Other Assets (33.6 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.1 %
iShares ESG Aware MSCI EAFE ETF 19.8 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.8 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.4 %
iShares TIPS Bond ETF 0.5 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.1 %
iShares ESG Aware MSCI EAFE ETF 19.8 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.8 %
iShares Developed Real Estate Index Fund, Class K 4.2 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.4 %
iShares TIPS Bond ETF 0.5 %
​(a)
Excludes short-term securities.
C000220957 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2060 Fund
Class Name Class K Shares
Trading Symbol LEZKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2060 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $0(a)(b) 0.00%(a)(c)(d)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Rounds to less than $1.
​(c)
Annualized.
​(d)
Rounds to less than 0.01%.
Expenses Paid, Amount $ 0 [55],[56]
Expense Ratio, Percent 0.00% [55],[57],[58]
Net Assets $ 16,647,697
Holdings Count | Holding 12
Investment Company Portfolio Turnover 7.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $16,647,697
Number of Portfolio Holdings 12
Portfolio Turnover Rate 7%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 98.9 %
Money Market Funds 35.6 %
Fixed-Income Funds 1.0 %
Liabilities in Excess of Other Assets (35.5 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.3 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 0.8 %
iShares TIPS Bond ETF 0.2 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.3 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 0.8 %
iShares TIPS Bond ETF 0.2 %
​(a)
Excludes short-term securities.
C000220958 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2060 Fund
Class Name Investor A Shares
Trading Symbol LEZAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2060 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $16(a) 0.30%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 16 [59]
Expense Ratio, Percent 0.30% [59],[60]
Net Assets $ 16,647,697
Holdings Count | Holding 12
Investment Company Portfolio Turnover 7.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $16,647,697
Number of Portfolio Holdings 12
Portfolio Turnover Rate 7%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 98.9 %
Money Market Funds 35.6 %
Fixed-Income Funds 1.0 %
Liabilities in Excess of Other Assets (35.5 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.3 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 0.8 %
iShares TIPS Bond ETF 0.2 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.3 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 0.8 %
iShares TIPS Bond ETF 0.2 %
​(a)
Excludes short-term securities.
C000220956 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2060 Fund
Class Name Institutional Shares
Trading Symbol LEZIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2060 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $3(a) 0.05%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 3 [61]
Expense Ratio, Percent 0.05% [61],[62]
Net Assets $ 16,647,697
Holdings Count | Holding 12
Investment Company Portfolio Turnover 7.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $16,647,697
Number of Portfolio Holdings 12
Portfolio Turnover Rate 7%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 98.9 %
Money Market Funds 35.6 %
Fixed-Income Funds 1.0 %
Liabilities in Excess of Other Assets (35.5 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.3 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 0.8 %
iShares TIPS Bond ETF 0.2 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 50.7 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.6 %
iShares ESG Aware MSCI USA Small-Cap ETF 5.9 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.3 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.5 %
iShares ESG Aware U.S. Aggregate Bond ETF 0.8 %
iShares TIPS Bond ETF 0.2 %
​(a)
Excludes short-term securities.
C000244506 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock Diversified Fixed Income Fund
Class Name Institutional Shares
Trading Symbol BDVIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock Diversified Fixed Income Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 537‑4942.
Additional Information Phone Number (800) 537‑4942
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $12 0.24%(a)
​(a)
Annualized.
Expenses Paid, Amount $ 12
Expense Ratio, Percent 0.24% [63]
Net Assets $ 1,274,480,131
Holdings Count | Holding 4,623
Investment Company Portfolio Turnover 603.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $1,274,480,131
Number of Portfolio Holdings 4,623
Portfolio Turnover Rate 603%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Investment Type Percent of Total
Investments(a)
U.S. Government Sponsored Agency Securities 36.0 %
Corporate Bonds 23.6 %
U.S. Treasury Obligations 22.9 %
Non-Agency Mortgage-Backed Securities 10.4 %
Asset-Backed Securities 4.6 %
Foreign Agency Obligations 1.2 %
Capital Trusts 0.5 %
Investment Companies 0.4 %
Municipal Bonds 0.3 %
Common Stocks 0.1 %
Other* — %(b)
Credit quality allocation
Credit Rating(c) Percent of Total
Investments(a)
AAA/Aaa(d) 3.4 %
AA/Aa 61.6 %
A 9.0 %
BBB/Baa 15.2 %
BB/Ba 3.1 %
B 0.8 %
CCC/Caa 0.4 %
CC 0.1 %
C — %(b)
D — %(b)
N/R 6.4 %
​(a)
Excludes short-term securities, short investments and options, if any.
​(b)
Rounds to less than 0.1%.
​(c)
For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
​(d)
The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
​*
Ten largest investment types are presented. Additional investment types are found in Other.
Credit Quality Explanation [Text Block] The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Ratings Selection [Text Block] For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
C000244507 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock Diversified Fixed Income Fund
Class Name Class K Shares
Trading Symbol BDVFX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock Diversified Fixed Income Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 537‑4942.
Additional Information Phone Number (800) 537‑4942
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $7 0.14%(a)
​(a)
Annualized.
Expenses Paid, Amount $ 7
Expense Ratio, Percent 0.14% [64]
Net Assets $ 1,274,480,131
Holdings Count | Holding 4,623
Investment Company Portfolio Turnover 603.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $1,274,480,131
Number of Portfolio Holdings 4,623
Portfolio Turnover Rate 603%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Investment Type Percent of Total
Investments(a)
U.S. Government Sponsored Agency Securities 36.0 %
Corporate Bonds 23.6 %
U.S. Treasury Obligations 22.9 %
Non-Agency Mortgage-Backed Securities 10.4 %
Asset-Backed Securities 4.6 %
Foreign Agency Obligations 1.2 %
Capital Trusts 0.5 %
Investment Companies 0.4 %
Municipal Bonds 0.3 %
Common Stocks 0.1 %
Other* — %(b)
Credit quality allocation
Credit Rating(c) Percent of Total
Investments(a)
AAA/Aaa(d) 3.4 %
AA/Aa 61.6 %
A 9.0 %
BBB/Baa 15.2 %
BB/Ba 3.1 %
B 0.8 %
CCC/Caa 0.4 %
CC 0.1 %
C — %(b)
D — %(b)
N/R 6.4 %
​(a)
Excludes short-term securities, short investments and options, if any.
​(b)
Rounds to less than 0.1%.
​(c)
For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
​(d)
The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
​*
Ten largest investment types are presented. Additional investment types are found in Other.
Credit Quality Explanation [Text Block] The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Ratings Selection [Text Block] For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
C000251819 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2070 Fund
Class Name Class K Shares
Trading Symbol LEYKX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2070 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $0(a)(b) 0.00%(a)(c)(d)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Rounds to less than $1.
​(c)
Annualized.
​(d)
Rounds to less than 0.01%.
Expenses Paid, Amount $ 0 [65],[66]
Expense Ratio, Percent 0.00% [65],[67],[68]
Net Assets $ 3,083,452
Holdings Count | Holding 11
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $3,083,452
Number of Portfolio Holdings 11
Portfolio Turnover Rate 8%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 99.5 %
Money Market Funds 37.8 %
Fixed-Income Funds 1.0 %
Liabilities in Excess of Other Assets (38.3 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 51.0 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 6.0 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 51.0 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 6.0 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
C000251818 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2070 Fund
Class Name Investor A Shares
Trading Symbol LEYAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2070 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $16(a) 0.30%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 16 [69]
Expense Ratio, Percent 0.30% [69],[70]
Net Assets $ 3,083,452
Holdings Count | Holding 11
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $3,083,452
Number of Portfolio Holdings 11
Portfolio Turnover Rate 8%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 99.5 %
Money Market Funds 37.8 %
Fixed-Income Funds 1.0 %
Liabilities in Excess of Other Assets (38.3 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 51.0 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 6.0 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 51.0 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 6.0 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
C000251817 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock LifePath® ESG Index 2070 Fund
Class Name Institutional Shares
Trading Symbol LEYIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock LifePath® ESG Index 2070 Fund (the “Fund”) for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months ?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $3(a) 0.05%(a)(b)
​(a)
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
​(b)
Annualized.
Expenses Paid, Amount $ 3 [71]
Expense Ratio, Percent 0.05% [71],[72]
Net Assets $ 3,083,452
Holdings Count | Holding 11
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $3,083,452
Number of Portfolio Holdings 11
Portfolio Turnover Rate 8%
Holdings [Text Block]
What did the Fund invest in?
(as of April 30, 2026)
Portfolio composition
Asset Type Percent of
Net Assets
Equity Funds 99.5 %
Money Market Funds 37.8 %
Fixed-Income Funds 1.0 %
Liabilities in Excess of Other Assets (38.3 )
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 51.0 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 6.0 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
Largest Holdings [Text Block]
Ten largest holdings
Security(a) Percent of
Net Assets
iShares ESG Aware MSCI USA ETF 51.0 %
iShares ESG Aware MSCI EAFE ETF 20.1 %
iShares ESG Aware MSCI EM ETF 10.8 %
iShares ESG Aware MSCI USA Small-Cap ETF 6.0 %
iShares Developed Real Estate Index Fund, Class K 4.1 %
iShares MSCI EAFE Small-Cap ETF 3.2 %
iShares MSCI Canada ETF 2.7 %
iShares MSCI Emerging Markets Small-Cap ETF 1.6 %
iShares ESG Aware U.S. Aggregate Bond ETF 1.0 %
​(a)
Excludes short-term securities.
[1]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[2] Annualized.
[3]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[4] Annualized.
[5]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[6] Annualized.
[7] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[8] Annualized.
[9] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[10] Annualized.
[11] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[12] Rounds to less than $1.
[13] Annualized.
[14] Rounds to less than 0.01%.
[15]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[16]
Annualized.
[17]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[18] Annualized.
[19]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[20] Annualized.
[21]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[22]
Annualized.
[23]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[24]
Annualized.
[25]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[26]
Annualized.
[27]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[28]
Annualized.
[29]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[30]
Annualized.
[31]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[32]
Annualized.
[33]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[34]
Annualized.
[35] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[36] Annualized.
[37] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[38] Annualized.
[39] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[40] Rounds to less than $1.
[41] Annualized.
[42] Rounds to less than 0.01%.
[43] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[44] Annualized.
[45] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[46] Annualized.
[47]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[48]
Annualized.
[49]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[50]
Annualized.
[51] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[52] Rounds to less than $1.
[53] Annualized.
[54] Rounds to less than 0.01%.
[55] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[56] Rounds to less than $1.
[57] Annualized.
[58] Rounds to less than 0.01%.
[59] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[60] Annualized.
[61]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[62]
Annualized.
[63]
Annualized.
[64]
Annualized.
[65] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[66] Rounds to less than $1.
[67] Annualized.
[68] Rounds to less than 0.01%.
[69]
Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[70] Annualized.
[71] Excludes fees and expenses incurred indirectly as a result of investments in underlying funds.
[72] Annualized.