v3.26.1
Shareholder Report, Holdings (Details)
Jun. 30, 2026
C000082487 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.00% [1]
C000082487 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [1]
C000082487 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [1]
C000082487 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [1]
C000082487 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80% [1]
C000082487 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00% [1]
C000082487 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.70% [1]
C000082487 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.20% [1]
C000082487 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.30% [1]
C000082487 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 32.10% [1]
C000082487 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [2]
C000082487 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 58.20% [2]
C000082487 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.00% [2]
C000082487 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.20% [2]
C000051481 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.00% [3]
C000051481 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [3]
C000051481 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [3]
C000051481 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [3]
C000051481 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80% [3]
C000051481 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00% [3]
C000051481 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.70% [3]
C000051481 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.20% [3]
C000051481 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.30% [3]
C000051481 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 32.10% [3]
C000051481 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [4]
C000051481 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 58.20% [4]
C000051481 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.00% [4]
C000051481 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.20% [4]
C000088835 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.00% [5]
C000088835 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [5]
C000088835 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [5]
C000088835 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [5]
C000088835 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80% [5]
C000088835 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00% [5]
C000088835 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.70% [5]
C000088835 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.20% [5]
C000088835 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.30% [5]
C000088835 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 32.10% [5]
C000088835 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [6]
C000088835 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 58.20% [6]
C000088835 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.00% [6]
C000088835 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.20% [6]
C000011997 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.00% [7]
C000011997 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [7]
C000011997 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [7]
C000011997 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [7]
C000011997 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80% [7]
C000011997 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00% [7]
C000011997 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.70% [7]
C000011997 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.20% [7]
C000011997 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.30% [7]
C000011997 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 32.10% [7]
C000011997 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [8]
C000011997 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 58.20% [8]
C000011997 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.00% [8]
C000011997 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.20% [8]
C000011998 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.00% [9]
C000011998 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [9]
C000011998 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [9]
C000011998 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [9]
C000011998 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80% [9]
C000011998 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00% [9]
C000011998 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.70% [9]
C000011998 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.20% [9]
C000011998 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.30% [9]
C000011998 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 32.10% [9]
C000011998 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [10]
C000011998 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 58.20% [10]
C000011998 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.00% [10]
C000011998 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.20% [10]
C000012000 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.60% [11]
C000012000 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [11]
C000012000 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [11]
C000012000 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [11]
C000012000 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [11]
C000012000 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [11]
C000012000 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.40% [11]
C000012000 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.30% [11]
C000012000 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.30% [11]
C000012000 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50% [11]
C000012000 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 74.60% [12]
C000012000 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 20.30% [12]
C000012000 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [12]
C000012000 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [12],[13]
C000011999 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.60% [14]
C000011999 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [14]
C000011999 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [14]
C000011999 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [14]
C000011999 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [14]
C000011999 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [14]
C000011999 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.40% [14]
C000011999 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.30% [14]
C000011999 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.30% [14]
C000011999 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50% [14]
C000011999 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 74.60% [15]
C000011999 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 20.30% [15]
C000011999 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [15]
C000011999 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [15],[16]
C000088838 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.60% [17]
C000088838 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [17]
C000088838 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [17]
C000088838 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [17]
C000088838 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [17]
C000088838 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [17]
C000088838 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.40% [17]
C000088838 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.30% [17]
C000088838 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.30% [17]
C000088838 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50% [17]
C000088838 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 74.60% [18]
C000088838 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 20.30% [18]
C000088838 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [18]
C000088838 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [18],[19]
C000051482 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.60% [20]
C000051482 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [20]
C000051482 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [20]
C000051482 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [20]
C000051482 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [20]
C000051482 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [20]
C000051482 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.40% [20]
C000051482 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.30% [20]
C000051482 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.30% [20]
C000051482 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50% [20]
C000051482 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 74.60% [21]
C000051482 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 20.30% [21]
C000051482 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [21]
C000051482 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [21],[22]
C000082488 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.60% [23]
C000082488 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [23]
C000082488 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [23]
C000082488 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [23]
C000082488 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [23]
C000082488 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [23]
C000082488 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.40% [23]
C000082488 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.30% [23]
C000082488 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.30% [23]
C000082488 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50% [23]
C000082488 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 74.60% [24]
C000082488 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 20.30% [24]
C000082488 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [24]
C000082488 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [24],[25]
C000082489 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 41.60% [26]
C000082489 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [26]
C000082489 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [26]
C000082489 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [26]
C000082489 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [26]
C000082489 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20% [26]
C000082489 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.90% [26]
C000082489 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.70% [26]
C000082489 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.60% [26]
C000082489 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [26]
C000082489 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10% [27]
C000082489 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 45.20% [27]
C000082489 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.50% [27]
C000082489 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [27]
C000051483 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 41.60% [28]
C000051483 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [28]
C000051483 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [28]
C000051483 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [28]
C000051483 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [28]
C000051483 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20% [28]
C000051483 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.90% [28]
C000051483 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.70% [28]
C000051483 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.60% [28]
C000051483 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [28]
C000051483 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10% [29]
C000051483 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 45.20% [29]
C000051483 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.50% [29]
C000051483 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [29]
C000088841 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 41.60% [30]
C000088841 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [30]
C000088841 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [30]
C000088841 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [30]
C000088841 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [30]
C000088841 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20% [30]
C000088841 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.90% [30]
C000088841 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.70% [30]
C000088841 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.60% [30]
C000088841 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [30]
C000088841 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10% [31]
C000088841 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 45.20% [31]
C000088841 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.50% [31]
C000088841 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [31]
C000012001 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 41.60% [32]
C000012001 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [32]
C000012001 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [32]
C000012001 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [32]
C000012001 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [32]
C000012001 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20% [32]
C000012001 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.90% [32]
C000012001 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.70% [32]
C000012001 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.60% [32]
C000012001 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [32]
C000012001 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10% [33]
C000012001 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 45.20% [33]
C000012001 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.50% [33]
C000012001 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [33]
C000012002 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 41.60% [34]
C000012002 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [34]
C000012002 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [34]
C000012002 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [34]
C000012002 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [34]
C000012002 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20% [34]
C000012002 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.90% [34]
C000012002 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.70% [34]
C000012002 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.60% [34]
C000012002 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [34]
C000012002 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10% [35]
C000012002 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 45.20% [35]
C000012002 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.50% [35]
C000012002 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [35]
C000063261 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.50% [36]
C000063261 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [36]
C000063261 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [36]
C000063261 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40% [36]
C000063261 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [36]
C000063261 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.80% [36]
C000063261 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.70% [36]
C000063261 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.10% [36]
C000063261 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40% [36]
C000063261 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.60% [36]
C000063261 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.90% [37]
C000063261 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90% [37]
C000063261 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.30% [37]
C000063261 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.10%) [37]
C000063260 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.50% [38]
C000063260 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [38]
C000063260 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [38]
C000063260 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40% [38]
C000063260 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [38]
C000063260 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.80% [38]
C000063260 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.70% [38]
C000063260 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.10% [38]
C000063260 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40% [38]
C000063260 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.60% [38]
C000063260 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.90% [39]
C000063260 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90% [39]
C000063260 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.30% [39]
C000063260 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.10%) [39]
C000088844 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.50% [40]
C000088844 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [40]
C000088844 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [40]
C000088844 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40% [40]
C000088844 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [40]
C000088844 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.80% [40]
C000088844 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.70% [40]
C000088844 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.10% [40]
C000088844 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40% [40]
C000088844 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.60% [40]
C000088844 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.90% [41]
C000088844 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90% [41]
C000088844 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.30% [41]
C000088844 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.10%) [41]
C000063262 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.50% [42]
C000063262 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [42]
C000063262 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [42]
C000063262 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40% [42]
C000063262 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [42]
C000063262 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.80% [42]
C000063262 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.70% [42]
C000063262 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.10% [42]
C000063262 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40% [42]
C000063262 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.60% [42]
C000063262 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.90% [43]
C000063262 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90% [43]
C000063262 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.30% [43]
C000063262 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.10%) [43]
C000082490 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.50% [44]
C000082490 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [44]
C000082490 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [44]
C000082490 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40% [44]
C000082490 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [44]
C000082490 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.80% [44]
C000082490 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.70% [44]
C000082490 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.10% [44]
C000082490 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40% [44]
C000082490 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.60% [44]
C000082490 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.90% [45]
C000082490 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90% [45]
C000082490 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.30% [45]
C000082490 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.10%) [45]
C000089952 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 21.30% [46]
C000089952 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [46]
C000089952 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [46]
C000089952 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [46]
C000089952 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [46]
C000089952 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [46]
C000089952 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.20% [46]
C000089952 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [46]
C000089952 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.90% [46]
C000089952 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.70% [46]
C000089952 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [47]
C000089952 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 67.90% [47]
C000089952 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 26.50% [47]
C000089952 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.30% [47]
C000089956 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 21.30% [48]
C000089956 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [48]
C000089956 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [48]
C000089956 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [48]
C000089956 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [48]
C000089956 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [48]
C000089956 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.20% [48]
C000089956 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [48]
C000089956 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.90% [48]
C000089956 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.70% [48]
C000089956 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [49]
C000089956 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 67.90% [49]
C000089956 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 26.50% [49]
C000089956 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.30% [49]
C000089954 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 21.30% [50]
C000089954 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [50]
C000089954 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [50]
C000089954 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [50]
C000089954 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [50]
C000089954 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [50]
C000089954 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.20% [50]
C000089954 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [50]
C000089954 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.90% [50]
C000089954 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.70% [50]
C000089954 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [51]
C000089954 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 67.90% [51]
C000089954 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 26.50% [51]
C000089954 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.30% [51]
C000089953 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 21.30% [52]
C000089953 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [52]
C000089953 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [52]
C000089953 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [52]
C000089953 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [52]
C000089953 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [52]
C000089953 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.20% [52]
C000089953 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [52]
C000089953 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.90% [52]
C000089953 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.70% [52]
C000089953 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [53]
C000089953 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 67.90% [53]
C000089953 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 26.50% [53]
C000089953 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.30% [53]
C000089955 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 21.30% [54]
C000089955 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [54]
C000089955 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [54]
C000089955 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [54]
C000089955 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [54]
C000089955 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [54]
C000089955 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.20% [54]
C000089955 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [54]
C000089955 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.90% [54]
C000089955 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.70% [54]
C000089955 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [55]
C000089955 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 67.90% [55]
C000089955 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 26.50% [55]
C000089955 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.30% [55]
C000089959 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.60% [56]
C000089959 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.10% [56]
C000089959 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [56]
C000089959 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [56]
C000089959 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30% [56]
C000089959 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [56]
C000089959 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [56]
C000089959 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.90% [56]
C000089959 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 41.60% [56]
C000089959 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [56]
C000089959 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 80.90% [57]
C000089959 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.90% [57]
C000089959 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.80% [57]
C000089959 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.60%) [57]
C000089957 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.60% [58]
C000089957 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.10% [58]
C000089957 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [58]
C000089957 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [58]
C000089957 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30% [58]
C000089957 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [58]
C000089957 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [58]
C000089957 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.90% [58]
C000089957 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 41.60% [58]
C000089957 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [58]
C000089957 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 80.90% [59]
C000089957 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.90% [59]
C000089957 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.80% [59]
C000089957 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.60%) [59]
C000089958 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.60% [60]
C000089958 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.10% [60]
C000089958 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [60]
C000089958 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [60]
C000089958 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30% [60]
C000089958 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [60]
C000089958 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [60]
C000089958 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.90% [60]
C000089958 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 41.60% [60]
C000089958 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [60]
C000089958 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 80.90% [61]
C000089958 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.90% [61]
C000089958 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.80% [61]
C000089958 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.60%) [61]
C000089960 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.60% [62]
C000089960 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.10% [62]
C000089960 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [62]
C000089960 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [62]
C000089960 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30% [62]
C000089960 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [62]
C000089960 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [62]
C000089960 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.90% [62]
C000089960 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 41.60% [62]
C000089960 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [62]
C000089960 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 80.90% [63]
C000089960 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.90% [63]
C000089960 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.80% [63]
C000089960 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.60%) [63]
C000089961 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.60% [64]
C000089961 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.10% [64]
C000089961 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [64]
C000089961 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [64]
C000089961 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30% [64]
C000089961 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [64]
C000089961 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [64]
C000089961 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.90% [64]
C000089961 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 41.60% [64]
C000089961 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [64]
C000089961 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 80.90% [65]
C000089961 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.90% [65]
C000089961 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.80% [65]
C000089961 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.60%) [65]
C000089966 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [66]
C000089966 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [66]
C000089966 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [66]
C000089966 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [66]
C000089966 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [66]
C000089966 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.10% [66]
C000089966 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.00% [66]
C000089966 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.60% [66]
C000089966 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.70% [66]
C000089966 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [66]
C000089966 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.70% [67]
C000089966 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [67]
C000089966 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.50% [67]
C000089966 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (9.10%) [67]
C000089965 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [68]
C000089965 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [68]
C000089965 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [68]
C000089965 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [68]
C000089965 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [68]
C000089965 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.10% [68]
C000089965 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.00% [68]
C000089965 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.60% [68]
C000089965 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.70% [68]
C000089965 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [68]
C000089965 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.70% [69]
C000089965 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [69]
C000089965 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.50% [69]
C000089965 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (9.10%) [69]
C000089963 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [70]
C000089963 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [70]
C000089963 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [70]
C000089963 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [70]
C000089963 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [70]
C000089963 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.10% [70]
C000089963 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.00% [70]
C000089963 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.60% [70]
C000089963 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.70% [70]
C000089963 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [70]
C000089963 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.70% [71]
C000089963 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [71]
C000089963 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.50% [71]
C000089963 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (9.10%) [71]
C000089962 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [72]
C000089962 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [72]
C000089962 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [72]
C000089962 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [72]
C000089962 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [72]
C000089962 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.10% [72]
C000089962 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.00% [72]
C000089962 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.60% [72]
C000089962 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.70% [72]
C000089962 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [72]
C000089962 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.70% [73]
C000089962 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [73]
C000089962 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.50% [73]
C000089962 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (9.10%) [73]
C000089964 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [74]
C000089964 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [74]
C000089964 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [74]
C000089964 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [74]
C000089964 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [74]
C000089964 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.10% [74]
C000089964 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.00% [74]
C000089964 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.60% [74]
C000089964 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.70% [74]
C000089964 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [74]
C000089964 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.70% [75]
C000089964 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [75]
C000089964 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.50% [75]
C000089964 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (9.10%) [75]
C000187070 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [76]
C000187070 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [76]
C000187070 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [76]
C000187070 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [76]
C000187070 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.90% [76]
C000187070 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10% [76]
C000187070 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.50% [76]
C000187070 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [76]
C000187070 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10% [76]
C000187070 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [76]
C000187070 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 94.10% [77]
C000187070 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [77]
C000187070 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10% [77]
C000187070 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (9.80%) [77]
C000187068 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [78]
C000187068 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [78]
C000187068 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [78]
C000187068 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [78]
C000187068 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.90% [78]
C000187068 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10% [78]
C000187068 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.50% [78]
C000187068 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [78]
C000187068 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10% [78]
C000187068 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [78]
C000187068 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 94.10% [79]
C000187068 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [79]
C000187068 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10% [79]
C000187068 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (9.80%) [79]
C000187069 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [80]
C000187069 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [80]
C000187069 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [80]
C000187069 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [80]
C000187069 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.90% [80]
C000187069 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10% [80]
C000187069 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.50% [80]
C000187069 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [80]
C000187069 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10% [80]
C000187069 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [80]
C000187069 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 94.10% [81]
C000187069 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [81]
C000187069 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10% [81]
C000187069 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (9.80%) [81]
C000187072 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [82]
C000187072 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [82]
C000187072 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [82]
C000187072 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [82]
C000187072 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.90% [82]
C000187072 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10% [82]
C000187072 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.50% [82]
C000187072 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [82]
C000187072 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10% [82]
C000187072 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [82]
C000187072 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 94.10% [83]
C000187072 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [83]
C000187072 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10% [83]
C000187072 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (9.80%) [83]
C000187071 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [84]
C000187071 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [84]
C000187071 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [84]
C000187071 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [84]
C000187071 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.90% [84]
C000187071 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10% [84]
C000187071 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.50% [84]
C000187071 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [84]
C000187071 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10% [84]
C000187071 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [84]
C000187071 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 94.10% [85]
C000187071 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [85]
C000187071 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10% [85]
C000187071 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (9.80%) [85]
C000213847 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [86]
C000213847 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [86]
C000213847 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [86]
C000213847 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.70% [86]
C000213847 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.70% [86]
C000213847 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [86]
C000213847 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.50% [86]
C000213847 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [86]
C000213847 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.80% [86]
C000213847 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [86]
C000213847 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 93.00% [87]
C000213847 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [87]
C000213847 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 16.20% [87]
C000213847 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (10.80%) [87]
C000213844 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [88]
C000213844 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [88]
C000213844 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [88]
C000213844 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.70% [88]
C000213844 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.70% [88]
C000213844 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [88]
C000213844 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.50% [88]
C000213844 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [88]
C000213844 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.80% [88]
C000213844 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [88]
C000213844 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 93.00% [89]
C000213844 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [89]
C000213844 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 16.20% [89]
C000213844 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (10.80%) [89]
C000213843 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [90]
C000213843 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [90]
C000213843 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [90]
C000213843 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.70% [90]
C000213843 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.70% [90]
C000213843 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [90]
C000213843 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.50% [90]
C000213843 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [90]
C000213843 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.80% [90]
C000213843 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [90]
C000213843 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 93.00% [91]
C000213843 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [91]
C000213843 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 16.20% [91]
C000213843 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (10.80%) [91]
C000213845 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [92]
C000213845 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [92]
C000213845 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [92]
C000213845 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.70% [92]
C000213845 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.70% [92]
C000213845 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [92]
C000213845 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.50% [92]
C000213845 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [92]
C000213845 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.80% [92]
C000213845 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [92]
C000213845 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 93.00% [93]
C000213845 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [93]
C000213845 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 16.20% [93]
C000213845 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (10.80%) [93]
C000213846 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [94]
C000213846 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [94]
C000213846 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [94]
C000213846 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.70% [94]
C000213846 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.70% [94]
C000213846 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [94]
C000213846 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.50% [94]
C000213846 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [94]
C000213846 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.80% [94]
C000213846 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [94]
C000213846 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 93.00% [95]
C000213846 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [95]
C000213846 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 16.20% [95]
C000213846 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (10.80%) [95]
C000251825 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [96]
C000251825 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [96]
C000251825 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [96]
C000251825 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.50% [96]
C000251825 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.90% [96]
C000251825 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.40% [96]
C000251825 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [96]
C000251825 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [96]
C000251825 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [96]
C000251825 [Member] | iShares Core MSCI EAFE ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [96]
C000251825 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.30% [97]
C000251825 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [97]
C000251825 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.20% [97]
C000251825 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (5.80%) [97]
C000251826 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [98]
C000251826 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [98]
C000251826 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [98]
C000251826 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.50% [98]
C000251826 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.90% [98]
C000251826 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.40% [98]
C000251826 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [98]
C000251826 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [98]
C000251826 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [98]
C000251826 [Member] | iShares Core MSCI EAFE ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [98]
C000251826 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.30% [99]
C000251826 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [99]
C000251826 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.20% [99]
C000251826 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (5.80%) [99]
C000251827 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [100]
C000251827 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [100]
C000251827 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [100]
C000251827 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.50% [100]
C000251827 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.90% [100]
C000251827 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.40% [100]
C000251827 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [100]
C000251827 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [100]
C000251827 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [100]
C000251827 [Member] | iShares Core MSCI EAFE ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [100]
C000251827 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.30% [101]
C000251827 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [101]
C000251827 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.20% [101]
C000251827 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (5.80%) [101]
C000251828 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [102]
C000251828 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [102]
C000251828 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [102]
C000251828 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.50% [102]
C000251828 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.90% [102]
C000251828 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.40% [102]
C000251828 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [102]
C000251828 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [102]
C000251828 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [102]
C000251828 [Member] | iShares Core MSCI EAFE ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [102]
C000251828 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.30% [103]
C000251828 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [103]
C000251828 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.20% [103]
C000251828 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (5.80%) [103]
C000251824 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [104]
C000251824 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [104]
C000251824 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [104]
C000251824 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.50% [104]
C000251824 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.90% [104]
C000251824 [Member] | Diversified Equity Alpha Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.40% [104]
C000251824 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [104]
C000251824 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [104]
C000251824 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [104]
C000251824 [Member] | iShares Core MSCI EAFE ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [104]
C000251824 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.30% [105]
C000251824 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [105]
C000251824 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.20% [105]
C000251824 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (5.80%) [105]
[1] Excludes short-term securities.
[2] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[3]
Excludes short-term securities.
[4]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[5]
Excludes short-term securities.
[6]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[7]
Excludes short-term securities.
[8]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[9] Excludes short-term securities.
[10] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[11] Excludes short-term securities.
[12] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[13] Rounds to greater than (0.1)%.
[14] Excludes short-term securities.
[15] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[16] Rounds to greater than (0.1)%.
[17] Excludes short-term securities.
[18] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[19] Rounds to greater than (0.1)%.
[20] Excludes short-term securities.
[21] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[22] Rounds to greater than (0.1)%.
[23] Excludes short-term securities.
[24] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[25] Rounds to greater than (0.1)%.
[26]
Excludes short-term securities.
[27]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[28]
Excludes short-term securities.
[29]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[30] Excludes short-term securities.
[31] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[32] Excludes short-term securities.
[33] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[34]
Excludes short-term securities.
[35]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[36] Excludes short-term securities.
[37] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[38] Excludes short-term securities.
[39] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[40] Excludes short-term securities.
[41] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[42] Excludes short-term securities.
[43] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[44] Excludes short-term securities.
[45] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[46] Excludes short-term securities.
[47] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[48] Excludes short-term securities.
[49] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[50] Excludes short-term securities.
[51] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[52]
Excludes short-term securities.
[53]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[54]
Excludes short-term securities.
[55]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[56]
Excludes short-term securities.
[57]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[58]
Excludes short-term securities.
[59]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[60]
Excludes short-term securities.
[61]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[62]
Excludes short-term securities.
[63]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[64]
Excludes short-term securities.
[65]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[66] Excludes short-term securities.
[67] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[68] Excludes short-term securities.
[69] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[70] Excludes short-term securities.
[71] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[72] Excludes short-term securities.
[73] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[74] Excludes short-term securities.
[75] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[76] Excludes short-term securities.
[77] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[78] Excludes short-term securities.
[79] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[80] Excludes short-term securities.
[81] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[82] Excludes short-term securities.
[83] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[84] Excludes short-term securities.
[85] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[86] Excludes short-term securities.
[87] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[88] Excludes short-term securities.
[89] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[90] Excludes short-term securities.
[91] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[92] Excludes short-term securities.
[93] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[94] Excludes short-term securities.
[95] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[96] Excludes short-term securities.
[97] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[98] Excludes short-term securities.
[99] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[100]
Excludes short-term securities.
[101]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[102]
Excludes short-term securities.
[103]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[104]
Excludes short-term securities.
[105]
The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.