v3.25.4
Shareholder Report, Holdings (Details)
Dec. 31, 2025
C000101136 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [1]
C000101136 [Member] | iShares Enhanced Roll Yield Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [1]
C000101136 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [1]
C000101136 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [1]
C000101136 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10% [1]
C000101136 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [1]
C000101136 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.70% [1]
C000101136 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.10% [1]
C000101136 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 21.20% [1]
C000101136 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 22.60% [1]
C000101136 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [2]
C000101136 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.10%
C000101136 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 59.90%
C000101136 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [2]
C000201968 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [3]
C000201968 [Member] | iShares Enhanced Roll Yield Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [3]
C000201968 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [3]
C000201968 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [3]
C000201968 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10% [3]
C000201968 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [3]
C000201968 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.70% [3]
C000201968 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.10% [3]
C000201968 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 21.20% [3]
C000201968 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 22.60% [3]
C000201968 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [4]
C000201968 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.10%
C000201968 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 59.90%
C000201968 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [4]
C000101134 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [5]
C000101134 [Member] | iShares Enhanced Roll Yield Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [5]
C000101134 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [5]
C000101134 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [5]
C000101134 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10% [5]
C000101134 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [5]
C000101134 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.70% [5]
C000101134 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.10% [5]
C000101134 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 21.20% [5]
C000101134 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 22.60% [5]
C000101134 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [6]
C000101134 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.10%
C000101134 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 59.90%
C000101134 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [6]
C000101135 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50% [7]
C000101135 [Member] | iShares Enhanced Roll Yield Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [7]
C000101135 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30% [7]
C000101135 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.50% [7]
C000101135 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10% [7]
C000101135 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.70% [7]
C000101135 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.70% [7]
C000101135 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.10% [7]
C000101135 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 21.20% [7]
C000101135 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 22.60% [7]
C000101135 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [8]
C000101135 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.10%
C000101135 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 59.90%
C000101135 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [8]
C000101144 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [9]
C000101144 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [9]
C000101144 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [9]
C000101144 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [9]
C000101144 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.90% [9]
C000101144 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.40% [9]
C000101144 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.70% [9]
C000101144 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.30% [9]
C000101144 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 28.60% [9]
C000101144 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [9]
C000101144 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.00%
C000101144 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.00%
C000101144 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000101144 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.10%)
C000101143 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [10]
C000101143 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [10]
C000101143 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [10]
C000101143 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [10]
C000101143 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.90% [10]
C000101143 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.40% [10]
C000101143 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.70% [10]
C000101143 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.30% [10]
C000101143 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 28.60% [10]
C000101143 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [10]
C000101143 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.00%
C000101143 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.00%
C000101143 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000101143 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.10%)
C000201971 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [11]
C000201971 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [11]
C000201971 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [11]
C000201971 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [11]
C000201971 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.90% [11]
C000201971 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.40% [11]
C000201971 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.70% [11]
C000201971 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.30% [11]
C000201971 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 28.60% [11]
C000201971 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [11]
C000201971 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.00%
C000201971 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.00%
C000201971 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000201971 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.10%)
C000101145 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60% [12]
C000101145 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [12]
C000101145 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [12]
C000101145 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [12]
C000101145 [Member] | iShares 0 5 Year TIPS Bond ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.90% [12]
C000101145 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.40% [12]
C000101145 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.70% [12]
C000101145 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.30% [12]
C000101145 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 28.60% [12]
C000101145 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [12]
C000101145 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.00%
C000101145 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 49.00%
C000101145 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000101145 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.10%)
C000101148 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [13]
C000101148 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [13]
C000101148 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [13]
C000101148 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [13]
C000101148 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 22.40% [13]
C000101148 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.50% [13]
C000101148 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.00% [13]
C000101148 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.10% [13]
C000101148 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.60% [13]
C000101148 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [13]
C000101148 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 62.90%
C000101148 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.10%
C000101148 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.00%) [14]
C000201972 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [15]
C000201972 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [15]
C000201972 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [15]
C000201972 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [15]
C000201972 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 22.40% [15]
C000201972 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.50% [15]
C000201972 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.00% [15]
C000201972 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.10% [15]
C000201972 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.60% [15]
C000201972 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [15]
C000201972 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 62.90%
C000201972 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.10%
C000201972 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.00%) [16]
C000101146 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [17]
C000101146 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [17]
C000101146 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [17]
C000101146 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [17]
C000101146 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 22.40% [17]
C000101146 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.50% [17]
C000101146 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.00% [17]
C000101146 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.10% [17]
C000101146 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.60% [17]
C000101146 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [17]
C000101146 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 62.90%
C000101146 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.10%
C000101146 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.00%) [18]
C000101147 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [19]
C000101147 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90% [19]
C000101147 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.60% [19]
C000101147 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [19]
C000101147 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 22.40% [19]
C000101147 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.50% [19]
C000101147 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.00% [19]
C000101147 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.10% [19]
C000101147 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.60% [19]
C000101147 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [19]
C000101147 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 62.90%
C000101147 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.10%
C000101147 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.00%) [20]
C000101150 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [21]
C000101150 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [21]
C000101150 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [21]
C000101150 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40% [21]
C000101150 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 26.80% [21]
C000101150 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.60% [21]
C000101150 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [21]
C000101150 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.80% [21]
C000101150 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [21]
C000101150 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [21]
C000101150 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 74.60%
C000101150 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 25.40%
C000101150 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000101150 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.20%)
C000101149 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [22]
C000101149 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [22]
C000101149 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [22]
C000101149 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40% [22]
C000101149 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 26.80% [22]
C000101149 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.60% [22]
C000101149 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [22]
C000101149 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.80% [22]
C000101149 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [22]
C000101149 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [22]
C000101149 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 74.60%
C000101149 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 25.40%
C000101149 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000101149 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.20%)
C000201973 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [23]
C000201973 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [23]
C000201973 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [23]
C000201973 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40% [23]
C000201973 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 26.80% [23]
C000201973 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.60% [23]
C000201973 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [23]
C000201973 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.80% [23]
C000201973 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [23]
C000201973 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [23]
C000201973 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 74.60%
C000201973 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 25.40%
C000201973 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000201973 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.20%)
C000101151 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00% [24]
C000101151 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [24]
C000101151 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.50% [24]
C000101151 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40% [24]
C000101151 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 26.80% [24]
C000101151 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.60% [24]
C000101151 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.40% [24]
C000101151 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 40.80% [24]
C000101151 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [24]
C000101151 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [24]
C000101151 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 74.60%
C000101151 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 25.40%
C000101151 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000101151 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.20%)
C000101154 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [25]
C000101154 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [25]
C000101154 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [25]
C000101154 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [25]
C000101154 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 31.70% [25]
C000101154 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [25]
C000101154 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [25]
C000101154 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.20% [25]
C000101154 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10% [25]
C000101154 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [25]
C000101154 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 85.10%
C000101154 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.90%
C000101154 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [26]
C000101154 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [27]
C000201974 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [28]
C000201974 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [28]
C000201974 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [28]
C000201974 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [28]
C000201974 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 31.70% [28]
C000201974 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [28]
C000201974 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [28]
C000201974 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.20% [28]
C000201974 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10% [28]
C000201974 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [28]
C000201974 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 85.10%
C000201974 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.90%
C000201974 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [29]
C000201974 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value [30]
C000101152 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [31]
C000101152 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [31]
C000101152 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [31]
C000101152 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [31]
C000101152 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 31.70% [31]
C000101152 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [31]
C000101152 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [31]
C000101152 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.20% [31]
C000101152 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10% [31]
C000101152 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [31]
C000101152 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 85.10%
C000101152 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.90%
C000101152 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [32]
C000101152 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.00%) [33]
C000101153 [Member] | iShares Global Infrastructure ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.70% [34]
C000101153 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30% [34]
C000101153 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20% [34]
C000101153 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [34]
C000101153 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 31.70% [34]
C000101153 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90% [34]
C000101153 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [34]
C000101153 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.20% [34]
C000101153 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10% [34]
C000101153 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50% [34]
C000101153 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 85.10%
C000101153 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.90%
C000101153 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [35]
C000101153 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.00%) [36]
C000101156 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80% [37]
C000101156 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [37]
C000101156 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [37]
C000101156 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.00% [37]
C000101156 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [37]
C000101156 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [37]
C000101156 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.90% [37]
C000101156 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.70% [37]
C000101156 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [37]
C000101156 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 93.80%
C000101156 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30%
C000101156 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.10%)
C000101155 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80% [38]
C000101155 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [38]
C000101155 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [38]
C000101155 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.00% [38]
C000101155 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [38]
C000101155 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [38]
C000101155 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.90% [38]
C000101155 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.70% [38]
C000101155 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [38]
C000101155 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 93.80%
C000101155 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30%
C000101155 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.10%)
C000201975 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80% [39]
C000201975 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [39]
C000201975 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [39]
C000201975 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.00% [39]
C000201975 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [39]
C000201975 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [39]
C000201975 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.90% [39]
C000201975 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.70% [39]
C000201975 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [39]
C000201975 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 93.80%
C000201975 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30%
C000201975 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.10%)
C000101157 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80% [40]
C000101157 [Member] | iShares U S Intermediate Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20% [40]
C000101157 [Member] | iShares U S Long Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [40]
C000101157 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 36.00% [40]
C000101157 [Member] | iShares U S Securitized Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70% [40]
C000101157 [Member] | iShares U S Intermediate Government Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30% [40]
C000101157 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 51.90% [40]
C000101157 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.70% [40]
C000101157 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20% [40]
C000101157 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 93.80%
C000101157 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30%
C000101157 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.10%)
C000101160 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [41]
C000101160 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.50% [41]
C000101160 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.10% [41]
C000101160 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [41]
C000101160 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [41]
C000101160 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 98.50%
C000101160 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000101160 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000101160 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.50%)
C000201976 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [42]
C000201976 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.50% [42]
C000201976 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.10% [42]
C000201976 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [42]
C000201976 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [42]
C000201976 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 98.50%
C000201976 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000201976 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000201976 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.50%)
C000101158 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [43]
C000101158 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.50% [43]
C000101158 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.10% [43]
C000101158 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [43]
C000101158 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [43]
C000101158 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 98.50%
C000101158 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000101158 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000101158 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.50%)
C000101159 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.80% [44]
C000101159 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.50% [44]
C000101159 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.10% [44]
C000101159 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.30% [44]
C000101159 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [44]
C000101159 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 98.50%
C000101159 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000101159 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000101159 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.50%)
C000166218 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [45]
C000166218 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.80% [45]
C000166218 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.80% [45]
C000166218 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [45]
C000166218 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [45]
C000166218 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.20%
C000166218 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000166218 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000166218 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.40%)
C000166217 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [46]
C000166217 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.80% [46]
C000166217 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.80% [46]
C000166217 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [46]
C000166217 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [46]
C000166217 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.20%
C000166217 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000166217 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000166217 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.40%)
C000201977 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [47]
C000201977 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.80% [47]
C000201977 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.80% [47]
C000201977 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [47]
C000201977 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [47]
C000201977 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.20%
C000201977 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000201977 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000201977 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.40%)
C000166219 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [48]
C000166219 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.80% [48]
C000166219 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.80% [48]
C000166219 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [48]
C000166219 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [48]
C000166219 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.20%
C000166219 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000166219 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000166219 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.40%)
C000213835 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [49]
C000213835 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.60% [49]
C000213835 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.80% [49]
C000213835 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [49]
C000213835 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [49]
C000213835 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.00%
C000213835 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000213835 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000213835 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.30%)
C000213838 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [50]
C000213838 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.60% [50]
C000213838 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.80% [50]
C000213838 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [50]
C000213838 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [50]
C000213838 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.00%
C000213838 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000213838 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000213838 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.30%)
C000213836 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [51]
C000213836 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.60% [51]
C000213836 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.80% [51]
C000213836 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [51]
C000213836 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [51]
C000213836 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.00%
C000213836 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000213836 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000213836 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.30%)
C000213837 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [52]
C000213837 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 38.60% [52]
C000213837 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 55.80% [52]
C000213837 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [52]
C000213837 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.60% [52]
C000213837 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.00%
C000213837 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000213837 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000213837 [Member] | Liabilities in Excess of Other Assets [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (0.30%)
C000251822 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [53]
C000251822 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.10% [53]
C000251822 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 56.00% [53]
C000251822 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [53]
C000251822 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.70% [53]
C000251822 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
C000251822 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 97.80%
C000251822 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000251822 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000251821 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [54]
C000251821 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.10% [54]
C000251821 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 56.00% [54]
C000251821 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [54]
C000251821 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.70% [54]
C000251821 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
C000251821 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 97.80%
C000251821 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000251821 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000251823 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [55]
C000251823 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.10% [55]
C000251823 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 56.00% [55]
C000251823 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [55]
C000251823 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.70% [55]
C000251823 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
C000251823 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 97.80%
C000251823 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000251823 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000251820 [Member] | iShares U S Long Credit Bond Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [56]
C000251820 [Member] | iShares Core MSCI Total International Stock ETF [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.10% [56]
C000251820 [Member] | Large Cap Index Master Portfolio [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 56.00% [56]
C000251820 [Member] | iShares FTSE NAREIT All Equity REITs Index Fund [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [56]
C000251820 [Member] | Master Small Cap Index Series [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.70% [56]
C000251820 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
C000251820 [Member] | Equity Funds Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 97.80%
C000251820 [Member] | Fixed Income Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000251820 [Member] | Money Market Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
[1] Excludes short-term securities.
[2] Rounds to less than 0.1%.
[3] Excludes short-term securities.
[4] Rounds to less than 0.1%.
[5] Excludes short-term securities.
[6] Rounds to less than 0.1%.
[7] Excludes short-term securities.
[8] Rounds to less than 0.1%.
[9] Excludes short-term securities.
[10] Excludes short-term securities.
[11] Excludes short-term securities.
[12] Excludes short-term securities.
[13] Excludes short-term securities.
[14] Rounds to greater than (0.1)%.
[15] Excludes short-term securities.
[16] Rounds to greater than (0.1)%.
[17] Excludes short-term securities.
[18] Rounds to greater than (0.1)%.
[19] Excludes short-term securities.
[20] Rounds to greater than (0.1)%.
[21] Excludes short-term securities.
[22] Excludes short-term securities.
[23] Excludes short-term securities.
[24] Excludes short-term securities.
[25] Excludes short-term securities.
[26] Rounds to less than 0.1%.
[27] Rounds to greater than (0.1)%.
[28] Excludes short-term securities.
[29] Rounds to less than 0.1%.
[30] Rounds to greater than (0.1)%.
[31] Excludes short-term securities.
[32] Rounds to less than 0.1%.
[33] Rounds to greater than (0.1)%.
[34] Excludes short-term securities.
[35] Rounds to less than 0.1%.
[36] Rounds to greater than (0.1)%.
[37] Excludes short-term securities.
[38] Excludes short-term securities.
[39] Excludes short-term securities.
[40] Excludes short-term securities.
[41] Excludes short-term securities.
[42] Excludes short-term securities.
[43] Excludes short-term securities.
[44] Excludes short-term securities.
[45] Excludes short-term securities.
[46] Excludes short-term securities.
[47] Excludes short-term securities.
[48] Excludes short-term securities.
[49] Excludes short-term securities.
[50] Excludes short-term securities.
[51] Excludes short-term securities.
[52] Excludes short-term securities.
[53] Excludes short-term securities.
[54] Excludes short-term securities.
[55] Excludes short-term securities.
[56] Excludes short-term securities.