v3.25.4
Shareholder Report, Holdings (Details)
Dec. 31, 2025
C000082487 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40% [1]
C000082487 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [1]
C000082487 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [1]
C000082487 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.70% [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 5.40% [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 10.00% [1]
C000082487 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 23.20% [1]
C000082487 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 30.40% [1]
C000082487 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.70%) [2]
C000082487 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.50% [2]
C000082487 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.10% [2]
C000082487 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.10% [2]
C000051481 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40% [3]
C000051481 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [3]
C000051481 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [3]
C000051481 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.70% [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 5.40% [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 10.00% [3]
C000051481 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 23.20% [3]
C000051481 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 30.40% [3]
C000051481 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.70%) [4]
C000051481 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.50% [4]
C000051481 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.10% [4]
C000051481 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.10% [4]
C000088835 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40% [5]
C000088835 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [5]
C000088835 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [5]
C000088835 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.70% [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 5.40% [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 10.00% [5]
C000088835 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 23.20% [5]
C000088835 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 30.40% [5]
C000088835 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.70%) [6]
C000088835 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.50% [6]
C000088835 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.10% [6]
C000088835 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.10% [6]
C000011997 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40% [7]
C000011997 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [7]
C000011997 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [7]
C000011997 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.70% [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 5.40% [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 10.00% [7]
C000011997 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 23.20% [7]
C000011997 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 30.40% [7]
C000011997 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.70%) [8]
C000011997 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.50% [8]
C000011997 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.10% [8]
C000011997 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.10% [8]
C000011998 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40% [9]
C000011998 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [9]
C000011998 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [9]
C000011998 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.70% [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 5.40% [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 10.00% [9]
C000011998 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 23.20% [9]
C000011998 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 30.40% [9]
C000011998 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.70%) [10]
C000011998 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.50% [10]
C000011998 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.10% [10]
C000011998 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.10% [10]
C000012000 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [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 1.90% [11]
C000012000 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40% [11]
C000012000 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [11]
C000012000 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [11]
C000012000 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.20% [11]
C000012000 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.20% [11]
C000012000 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.90% [11]
C000012000 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50% [11]
C000012000 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (3.60%) [12]
C000012000 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 73.00% [12]
C000012000 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 19.80% [12]
C000012000 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.80% [12]
C000011999 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [13]
C000011999 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [13]
C000011999 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [13]
C000011999 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40% [13]
C000011999 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [13]
C000011999 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [13]
C000011999 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.20% [13]
C000011999 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.20% [13]
C000011999 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.90% [13]
C000011999 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50% [13]
C000011999 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (3.60%) [14]
C000011999 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 73.00% [14]
C000011999 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 19.80% [14]
C000011999 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.80% [14]
C000088838 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [15]
C000088838 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [15]
C000088838 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [15]
C000088838 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40% [15]
C000088838 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [15]
C000088838 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [15]
C000088838 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.20% [15]
C000088838 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.20% [15]
C000088838 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.90% [15]
C000088838 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50% [15]
C000088838 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (3.60%) [16]
C000088838 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 73.00% [16]
C000088838 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 19.80% [16]
C000088838 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.80% [16]
C000051482 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [17]
C000051482 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [17]
C000051482 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [17]
C000051482 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40% [17]
C000051482 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [17]
C000051482 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [17]
C000051482 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.20% [17]
C000051482 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.20% [17]
C000051482 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.90% [17]
C000051482 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50% [17]
C000051482 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (3.60%) [18]
C000051482 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 73.00% [18]
C000051482 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 19.80% [18]
C000051482 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.80% [18]
C000082488 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [19]
C000082488 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [19]
C000082488 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [19]
C000082488 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40% [19]
C000082488 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [19]
C000082488 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [19]
C000082488 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.20% [19]
C000082488 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.20% [19]
C000082488 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.90% [19]
C000082488 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50% [19]
C000082488 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (3.60%) [20]
C000082488 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 73.00% [20]
C000082488 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 19.80% [20]
C000082488 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.80% [20]
C000082489 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [21]
C000082489 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [21]
C000082489 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [21]
C000082489 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [21]
C000082489 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [21]
C000082489 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.60% [21]
C000082489 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [21]
C000082489 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.50% [21]
C000082489 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.20% [21]
C000082489 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [21]
C000082489 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.50%) [22]
C000082489 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 43.90% [22]
C000082489 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.10% [22]
C000082489 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [22]
C000051483 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [23]
C000051483 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [23]
C000051483 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [23]
C000051483 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [23]
C000051483 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [23]
C000051483 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.60% [23]
C000051483 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [23]
C000051483 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.50% [23]
C000051483 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.20% [23]
C000051483 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [23]
C000051483 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.50%) [24]
C000051483 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 43.90% [24]
C000051483 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.10% [24]
C000051483 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [24]
C000088841 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [25]
C000088841 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [25]
C000088841 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [25]
C000088841 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [25]
C000088841 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [25]
C000088841 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.60% [25]
C000088841 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [25]
C000088841 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.50% [25]
C000088841 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.20% [25]
C000088841 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [25]
C000088841 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.50%) [26]
C000088841 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 43.90% [26]
C000088841 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.10% [26]
C000088841 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [26]
C000012001 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [27]
C000012001 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [27]
C000012001 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [27]
C000012001 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [27]
C000012001 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [27]
C000012001 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.60% [27]
C000012001 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [27]
C000012001 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.50% [27]
C000012001 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.20% [27]
C000012001 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [27]
C000012001 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.50%) [28]
C000012001 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 43.90% [28]
C000012001 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.10% [28]
C000012001 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [28]
C000012002 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [29]
C000012002 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [29]
C000012002 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [29]
C000012002 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [29]
C000012002 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [29]
C000012002 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.60% [29]
C000012002 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [29]
C000012002 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.50% [29]
C000012002 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 24.20% [29]
C000012002 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [29]
C000012002 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.50%) [30]
C000012002 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 43.90% [30]
C000012002 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.10% [30]
C000012002 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [30]
C000063261 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [31]
C000063261 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [31]
C000063261 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [31]
C000063261 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [31]
C000063261 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.20% [31]
C000063261 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10% [31]
C000063261 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [31]
C000063261 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 45.00% [31]
C000063261 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [31]
C000063261 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [31]
C000063261 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (10.40%) [32]
C000063261 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.00% [32]
C000063261 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.00% [32]
C000063261 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.40% [32]
C000063260 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [33]
C000063260 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [33]
C000063260 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [33]
C000063260 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [33]
C000063260 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.20% [33]
C000063260 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10% [33]
C000063260 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [33]
C000063260 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 45.00% [33]
C000063260 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [33]
C000063260 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [33]
C000063260 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (10.40%) [34]
C000063260 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.00% [34]
C000063260 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.00% [34]
C000063260 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.40% [34]
C000088844 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [35]
C000088844 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [35]
C000088844 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [35]
C000088844 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [35]
C000088844 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.20% [35]
C000088844 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10% [35]
C000088844 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [35]
C000088844 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 45.00% [35]
C000088844 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [35]
C000088844 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [35]
C000088844 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (10.40%) [36]
C000088844 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.00% [36]
C000088844 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.00% [36]
C000088844 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.40% [36]
C000063262 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [37]
C000063262 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [37]
C000063262 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [37]
C000063262 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [37]
C000063262 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.20% [37]
C000063262 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10% [37]
C000063262 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [37]
C000063262 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 45.00% [37]
C000063262 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [37]
C000063262 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [37]
C000063262 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (10.40%) [38]
C000063262 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.00% [38]
C000063262 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.00% [38]
C000063262 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.40% [38]
C000082490 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [39]
C000082490 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [39]
C000082490 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [39]
C000082490 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [39]
C000082490 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.20% [39]
C000082490 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10% [39]
C000082490 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [39]
C000082490 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 45.00% [39]
C000082490 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [39]
C000082490 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [39]
C000082490 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (10.40%) [40]
C000082490 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.00% [40]
C000082490 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.00% [40]
C000082490 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.40% [40]
C000089952 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [41]
C000089952 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [41]
C000089952 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [41]
C000089952 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [41]
C000089952 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [41]
C000089952 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.40% [41]
C000089952 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.30% [41]
C000089952 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 20.50% [41]
C000089952 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.30% [41]
C000089952 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [41]
C000089952 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (4.50%) [42]
C000089952 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 65.20% [42]
C000089952 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 25.50% [42]
C000089952 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.80% [42]
C000089956 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [43]
C000089956 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [43]
C000089956 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [43]
C000089956 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [43]
C000089956 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [43]
C000089956 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.40% [43]
C000089956 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.30% [43]
C000089956 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 20.50% [43]
C000089956 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.30% [43]
C000089956 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [43]
C000089956 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (4.50%) [44]
C000089956 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 65.20% [44]
C000089956 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 25.50% [44]
C000089956 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.80% [44]
C000089954 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [45]
C000089954 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [45]
C000089954 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [45]
C000089954 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [45]
C000089954 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [45]
C000089954 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.40% [45]
C000089954 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.30% [45]
C000089954 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 20.50% [45]
C000089954 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.30% [45]
C000089954 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [45]
C000089954 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (4.50%) [46]
C000089954 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 65.20% [46]
C000089954 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 25.50% [46]
C000089954 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.80% [46]
C000089953 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [47]
C000089953 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [47]
C000089953 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [47]
C000089953 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [47]
C000089953 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [47]
C000089953 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.40% [47]
C000089953 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.30% [47]
C000089953 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 20.50% [47]
C000089953 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.30% [47]
C000089953 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [47]
C000089953 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (4.50%) [48]
C000089953 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 65.20% [48]
C000089953 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 25.50% [48]
C000089953 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.80% [48]
C000089955 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [49]
C000089955 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [49]
C000089955 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [49]
C000089955 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [49]
C000089955 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [49]
C000089955 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.40% [49]
C000089955 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.30% [49]
C000089955 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 20.50% [49]
C000089955 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.30% [49]
C000089955 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [49]
C000089955 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (4.50%) [50]
C000089955 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 65.20% [50]
C000089955 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 25.50% [50]
C000089955 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.80% [50]
C000089959 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [51]
C000089959 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [51]
C000089959 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30% [51]
C000089959 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [51]
C000089959 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.90% [51]
C000089959 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [51]
C000089959 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.40% [51]
C000089959 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.30% [51]
C000089959 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [51]
C000089959 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [51]
C000089959 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.30%) [52]
C000089959 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 78.40% [52]
C000089959 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.60% [52]
C000089959 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 16.30% [52]
C000089957 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [53]
C000089957 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [53]
C000089957 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30% [53]
C000089957 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [53]
C000089957 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.90% [53]
C000089957 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [53]
C000089957 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.40% [53]
C000089957 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.30% [53]
C000089957 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [53]
C000089957 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [53]
C000089957 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.30%) [54]
C000089957 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 78.40% [54]
C000089957 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.60% [54]
C000089957 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 16.30% [54]
C000089958 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [55]
C000089958 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [55]
C000089958 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30% [55]
C000089958 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [55]
C000089958 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.90% [55]
C000089958 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [55]
C000089958 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.40% [55]
C000089958 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.30% [55]
C000089958 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [55]
C000089958 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [55]
C000089958 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.30%) [56]
C000089958 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 78.40% [56]
C000089958 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.60% [56]
C000089958 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 16.30% [56]
C000089960 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [57]
C000089960 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [57]
C000089960 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30% [57]
C000089960 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [57]
C000089960 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.90% [57]
C000089960 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [57]
C000089960 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.40% [57]
C000089960 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.30% [57]
C000089960 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [57]
C000089960 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [57]
C000089960 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.30%) [58]
C000089960 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 78.40% [58]
C000089960 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.60% [58]
C000089960 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 16.30% [58]
C000089961 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [59]
C000089961 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [59]
C000089961 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30% [59]
C000089961 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [59]
C000089961 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.90% [59]
C000089961 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [59]
C000089961 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.40% [59]
C000089961 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.30% [59]
C000089961 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.60% [59]
C000089961 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [59]
C000089961 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.30%) [60]
C000089961 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 78.40% [60]
C000089961 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.60% [60]
C000089961 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 16.30% [60]
C000089966 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [61]
C000089966 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [61]
C000089966 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40% [61]
C000089966 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [61]
C000089966 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.60% [61]
C000089966 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.00% [61]
C000089966 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [61]
C000089966 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.70% [61]
C000089966 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [61]
C000089966 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [61]
C000089966 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.10%) [62]
C000089966 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.20% [62]
C000089966 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [62]
C000089966 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.00% [62]
C000089965 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [63]
C000089965 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [63]
C000089965 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40% [63]
C000089965 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [63]
C000089965 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.60% [63]
C000089965 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.00% [63]
C000089965 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [63]
C000089965 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.70% [63]
C000089965 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [63]
C000089965 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [63]
C000089965 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.10%) [64]
C000089965 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.20% [64]
C000089965 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [64]
C000089965 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.00% [64]
C000089963 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [65]
C000089963 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [65]
C000089963 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40% [65]
C000089963 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [65]
C000089963 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.60% [65]
C000089963 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.00% [65]
C000089963 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [65]
C000089963 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.70% [65]
C000089963 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [65]
C000089963 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [65]
C000089963 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.10%) [66]
C000089963 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.20% [66]
C000089963 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [66]
C000089963 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.00% [66]
C000089962 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [67]
C000089962 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [67]
C000089962 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40% [67]
C000089962 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [67]
C000089962 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.60% [67]
C000089962 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.00% [67]
C000089962 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [67]
C000089962 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.70% [67]
C000089962 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [67]
C000089962 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [67]
C000089962 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.10%) [68]
C000089962 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.20% [68]
C000089962 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [68]
C000089962 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.00% [68]
C000089964 [Member] | BlackRock Real Estate Securities Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [69]
C000089964 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [69]
C000089964 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40% [69]
C000089964 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [69]
C000089964 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.60% [69]
C000089964 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.00% [69]
C000089964 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [69]
C000089964 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.70% [69]
C000089964 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [69]
C000089964 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [69]
C000089964 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (7.10%) [70]
C000089964 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.20% [70]
C000089964 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [70]
C000089964 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.00% [70]
C000187070 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [71]
C000187070 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [71]
C000187070 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [71]
C000187070 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.00% [71]
C000187070 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.70% [71]
C000187070 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [71]
C000187070 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.00% [71]
C000187070 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [71]
C000187070 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.20% [71]
C000187070 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [71]
C000187070 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (4.60%) [72]
C000187070 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.60% [72]
C000187070 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [72]
C000187070 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.20% [72]
C000187068 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [73]
C000187068 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [73]
C000187068 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [73]
C000187068 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.00% [73]
C000187068 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.70% [73]
C000187068 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [73]
C000187068 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.00% [73]
C000187068 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [73]
C000187068 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.20% [73]
C000187068 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [73]
C000187068 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (4.60%) [74]
C000187068 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.60% [74]
C000187068 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [74]
C000187068 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.20% [74]
C000187069 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [75]
C000187069 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [75]
C000187069 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [75]
C000187069 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.00% [75]
C000187069 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.70% [75]
C000187069 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [75]
C000187069 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.00% [75]
C000187069 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [75]
C000187069 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.20% [75]
C000187069 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [75]
C000187069 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (4.60%) [76]
C000187069 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.60% [76]
C000187069 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [76]
C000187069 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.20% [76]
C000187072 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [77]
C000187072 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [77]
C000187072 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [77]
C000187072 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.00% [77]
C000187072 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.70% [77]
C000187072 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [77]
C000187072 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.00% [77]
C000187072 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [77]
C000187072 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.20% [77]
C000187072 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [77]
C000187072 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (4.60%) [78]
C000187072 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.60% [78]
C000187072 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [78]
C000187072 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.20% [78]
C000187071 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [79]
C000187071 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [79]
C000187071 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80% [79]
C000187071 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.00% [79]
C000187071 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.70% [79]
C000187071 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [79]
C000187071 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.00% [79]
C000187071 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [79]
C000187071 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.20% [79]
C000187071 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [79]
C000187071 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (4.60%) [80]
C000187071 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.60% [80]
C000187071 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [80]
C000187071 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.20% [80]
C000213847 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [81]
C000213847 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [81]
C000213847 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [81]
C000213847 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [81]
C000213847 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.00% [81]
C000213847 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [81]
C000213847 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.50% [81]
C000213847 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [81]
C000213847 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.00% [81]
C000213847 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [81]
C000213847 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (3.80%) [82]
C000213847 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 87.40% [82]
C000213847 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [82]
C000213847 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [82]
C000213844 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [83]
C000213844 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [83]
C000213844 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [83]
C000213844 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [83]
C000213844 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.00% [83]
C000213844 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [83]
C000213844 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.50% [83]
C000213844 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [83]
C000213844 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.00% [83]
C000213844 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [83]
C000213844 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (3.80%) [84]
C000213844 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 87.40% [84]
C000213844 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [84]
C000213844 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [84]
C000213843 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [85]
C000213843 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [85]
C000213843 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [85]
C000213843 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [85]
C000213843 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.00% [85]
C000213843 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [85]
C000213843 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.50% [85]
C000213843 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [85]
C000213843 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.00% [85]
C000213843 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [85]
C000213843 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (3.80%) [86]
C000213843 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 87.40% [86]
C000213843 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [86]
C000213843 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [86]
C000213845 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [87]
C000213845 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [87]
C000213845 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [87]
C000213845 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [87]
C000213845 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.00% [87]
C000213845 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [87]
C000213845 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.50% [87]
C000213845 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [87]
C000213845 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.00% [87]
C000213845 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [87]
C000213845 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (3.80%) [88]
C000213845 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 87.40% [88]
C000213845 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [88]
C000213845 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [88]
C000213846 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.10% [89]
C000213846 [Member] | iShares Broad USD Investment Grade Corporate Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80% [89]
C000213846 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [89]
C000213846 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [89]
C000213846 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.00% [89]
C000213846 [Member] | BlackRock Diversified Fixed Income Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [89]
C000213846 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.50% [89]
C000213846 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [89]
C000213846 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.00% [89]
C000213846 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [89]
C000213846 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (3.80%) [90]
C000213846 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 87.40% [90]
C000213846 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [90]
C000213846 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.80% [90]
C000251825 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [91]
C000251825 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10% [91]
C000251825 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.60% [91]
C000251825 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.80% [91]
C000251825 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.00% [91]
C000251825 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40% [91]
C000251825 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30% [91]
C000251825 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [91]
C000251825 [Member] | iShares Core MSCI EAFE ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [91]
C000251825 [Member] | iShares MSCI Japan ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [91]
C000251825 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (12.80%) [92]
C000251825 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 97.40% [92]
C000251825 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [92]
C000251825 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10% [92]
C000251826 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [93]
C000251826 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10% [93]
C000251826 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.60% [93]
C000251826 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.80% [93]
C000251826 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.00% [93]
C000251826 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40% [93]
C000251826 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30% [93]
C000251826 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [93]
C000251826 [Member] | iShares Core MSCI EAFE ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [93]
C000251826 [Member] | iShares MSCI Japan ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [93]
C000251826 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (12.80%) [94]
C000251826 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 97.40% [94]
C000251826 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [94]
C000251826 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10% [94]
C000251827 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [95]
C000251827 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10% [95]
C000251827 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.60% [95]
C000251827 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.80% [95]
C000251827 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.00% [95]
C000251827 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40% [95]
C000251827 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30% [95]
C000251827 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [95]
C000251827 [Member] | iShares Core MSCI EAFE ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [95]
C000251827 [Member] | iShares MSCI Japan ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [95]
C000251827 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (12.80%) [96]
C000251827 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 97.40% [96]
C000251827 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [96]
C000251827 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10% [96]
C000251828 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [97]
C000251828 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10% [97]
C000251828 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.60% [97]
C000251828 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.80% [97]
C000251828 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.00% [97]
C000251828 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40% [97]
C000251828 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30% [97]
C000251828 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [97]
C000251828 [Member] | iShares Core MSCI EAFE ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [97]
C000251828 [Member] | iShares MSCI Japan ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [97]
C000251828 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (12.80%) [98]
C000251828 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 97.40% [98]
C000251828 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [98]
C000251828 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10% [98]
C000251824 [Member] | iShares MSCI EAFE Small Cap ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [99]
C000251824 [Member] | BlackRock Tactical Opportunities Fund Class K [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10% [99]
C000251824 [Member] | iShares Core MSCI Emerging Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 11.60% [99]
C000251824 [Member] | International Tilts Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.80% [99]
C000251824 [Member] | Diversified Equity Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 50.00% [99]
C000251824 [Member] | iShares MSCI Canada ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40% [99]
C000251824 [Member] | iShares Core MSCI International Developed Markets ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30% [99]
C000251824 [Member] | iShares Russell 2000 ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [99]
C000251824 [Member] | iShares Core MSCI EAFE ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [99]
C000251824 [Member] | iShares MSCI Japan ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00% [99]
C000251824 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (12.80%) [100]
C000251824 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 97.40% [100]
C000251824 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [100]
C000251824 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10% [100]
[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] Excludes short-term securities.
[14] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[15] Excludes short-term securities.
[16] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[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] Excludes short-term securities.
[20] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[21] Excludes short-term securities.
[22] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[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] Excludes short-term securities.
[26] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[27] Excludes short-term securities.
[28] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[29] Excludes short-term securities.
[30] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[31] Excludes short-term securities.
[32] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[33] Excludes short-term securities.
[34] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[35] Excludes short-term securities.
[36] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[37] Excludes short-term securities.
[38] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[39] Excludes short-term securities.
[40] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[41] Excludes short-term securities.
[42] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[43] Excludes short-term securities.
[44] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[45] Excludes short-term securities.
[46] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[47] Excludes short-term securities.
[48] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[49] Excludes short-term securities.
[50] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[51] Excludes short-term securities.
[52] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[53] Excludes short-term securities.
[54] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[55] Excludes short-term securities.
[56] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[57] Excludes short-term securities.
[58] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[59] Excludes short-term securities.
[60] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[61] Excludes short-term securities.
[62] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[63] Excludes short-term securities.
[64] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[65] Excludes short-term securities.
[66] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[67] Excludes short-term securities.
[68] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[69] Excludes short-term securities.
[70] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[71] Excludes short-term securities.
[72] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[73] Excludes short-term securities.
[74] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[75] Excludes short-term securities.
[76] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[77] Excludes short-term securities.
[78] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[79] Excludes short-term securities.
[80] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[81] Excludes short-term securities.
[82] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[83] Excludes short-term securities.
[84] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[85] Excludes short-term securities.
[86] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[87] Excludes short-term securities.
[88] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[89] Excludes short-term securities.
[90] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[91] Excludes short-term securities.
[92] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[93] Excludes short-term securities.
[94] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[95] Excludes short-term securities.
[96] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[97] Excludes short-term securities.
[98] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.
[99] Excludes short-term securities.
[100] The portfolio composition above is calculated using a methodology different than that disclosed in the Fund's prospectus.