| Label | Element | Value | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| DFA Oregon Municipal Bond Portfolio | DFA Oregon Municipal Bond Portfolio | |||||||||||
| Prospectus [Line Items] | oef_ProspectusLineItems | ||||||||||
| Risk/Return [Heading] | oef_RiskReturnHeading | DFA Oregon Municipal Bond Portfolio | |||||||||
| Shareholder Fees Caption [Optional Text] | oef_ShareholderFeesCaption | Shareholder Fees (fees paid directly from your investment) | |||||||||
| Operating Expenses Caption [Optional Text] | oef_OperatingExpensesCaption | Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) | |||||||||
| Expense Example [Heading] | oef_ExpenseExampleHeading | EXAMPLE | |||||||||
| Expense Example Narrative [Text Block] | oef_ExpenseExampleNarrativeTextBlock | This Example is meant to help you compare the cost of investing in the Portfolio with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Portfolio for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Portfolio’s operating expenses remain the same. The costs for the Portfolio reflect the net expenses of the Portfolio that result from the contractual expense waiver in the first year only. Although your actual costs may be higher or lower, based on these assumptions your costs whether you redeem or hold your shares would be: |
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| Supplement to Prospectus [Text Block] | oef_SupplementToProspectusTextBlock |
SUPPLEMENT TO THE STATUTORY
The purpose of this supplement to the Statutory Prospectuses dated February 28, 2026, as amended, of the portfolios listed above (each, a “Portfolio” and collectively, the “Portfolios”), each a series of DFA Investment Dimensions Group Inc. or Dimensional Investment Group Inc. (collectively, the “Funds”), is to notify shareholders that the Boards of Directors of the Funds approved reductions to the Portfolios’ management fees and reduced expense limitation amounts for the DFA Oregon Municipal Bond Portfolio and U.S. Large Company Portfolio, effective as of July 1, 2026, as described below. |
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| DFA Oregon Municipal Bond Portfolio | DFA Oregon Municipal Bond Portfolio | Institutional Class | |||||||||||
| Prospectus [Line Items] | oef_ProspectusLineItems | ||||||||||
| Management Fees (as a percentage of Assets) | oef_ManagementFeesOverAssets | 0.20% | [1] | ||||||||
| Other Expenses (as a percentage of Assets): | oef_OtherExpensesOverAssets | 0.09% | [1] | ||||||||
| Expenses (as a percentage of Assets) | oef_ExpensesOverAssets | 0.29% | [1] | ||||||||
| Fee Waiver or Reimbursement | oef_FeeWaiverOrReimbursementOverAssets | (0.04%) | [1],[2] | ||||||||
| Net Expenses (as a percentage of Assets) | oef_NetExpensesOverAssets | 0.25% | [1] | ||||||||
| Expense Example, with Redemption, 1 Year | oef_ExpenseExampleYear01 | $ 26 | |||||||||
| Expense Example, with Redemption, 3 Years | oef_ExpenseExampleYear03 | 89 | |||||||||
| Expense Example, with Redemption, 5 Years | oef_ExpenseExampleYear05 | 159 | |||||||||
| Expense Example, with Redemption, 10 Years | oef_ExpenseExampleYear10 | 364 | |||||||||
| Expense Example, No Redemption, 1 Year | oef_ExpenseExampleNoRedemptionYear01 | 26 | |||||||||
| Expense Example, No Redemption, 3 Years | oef_ExpenseExampleNoRedemptionYear03 | 89 | |||||||||
| Expense Example, No Redemption, 5 Years | oef_ExpenseExampleNoRedemptionYear05 | 159 | |||||||||
| Expense Example, No Redemption, 10 Years | oef_ExpenseExampleNoRedemptionYear10 | $ 364 | |||||||||
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