Global Bond Index Portfolio Fees and Expenses - Portfolio [Member] - Global Bond Index Portfolio |
Dec. 31, 2025 |
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| Prospectus [Line Items] | |
| Expense Heading [Optional Text] | <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Fees and Expenses</span> |
| Expense Narrative [Text Block] | The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the Fund. The expenses shown in the table and in the example that follows do not reflect additional fees and expenses associated with the annuity or life insurance program through which you invest. If those additional fees and expenses were included, overall expenses would be higher. |
| Operating Expenses Caption [Optional Text] | <span style="font-family:Arial;font-size:8.5pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="font-family:Arial;font-size:8.5pt;">(Expenses that you pay each year as a percentage of the value of your investment)</span> |
| Expense Example [Heading] | <span style="color:#000000;font-family:Arial;font-size:9.5pt;">Example</span> |
| Expense Example Narrative [Text Block] | This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. |
| Portfolio Turnover [Heading] | <span style="color:#000000;font-family:Arial;font-size:9.5pt;">Portfolio Turnover</span> |
| Portfolio Turnover [Text Block] | The Fund pays transaction costs, such as purchase fees, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 11% of the average value of its portfolio. |
| Portfolio Turnover, Rate | 11.00% |