SA Global Index Allocation 90-10 Portfolio Investment Strategy - SA Global Index Allocation 90-10 Portfolio	Dec. 31, 2025
Prospectus [Line Items]
Strategy [Heading]	<span style="color:#000000;font-family:Arial;font-size:12pt;font-style:italic;font-weight:bold;">Principal Investment Strategies of the Portfolio</span>
Strategy Narrative [Text Block]	The Portfolio is structured as a “fund-of-funds,” which means that it pursues its investment goal by investing its assets in a combination of other mutual funds (the “Underlying Portfolios”). The Underlying Portfolios will primarily include other funds in the Trust but may also include other funds advised by the Adviser. Under normal circumstances, the Portfolio will seek to allocate 90% of its assets (with a range of 80% to 100%) to Underlying Portfolios investing primarily in equity securities (“Underlying Equity Portfolios”) and 10% of its assets (with a range of 0% to 20%) to Underlying Portfolios investing primarily in fixed income securities (“Underlying Fixed Income Portfolios”). The Underlying Portfolios invest in, or obtain exposure to, equity or fixed income securities of U.S. or foreign corporate and governmental issuers. Certain Underlying Equity Portfolios invest in, or obtain exposure to, investments in a number of different countries around the world, which may include emerging markets (“Underlying International Portfolios”). Under normal circumstances, the Portfolio invests approximately half of its allocation to Underlying Equity Portfolios in Underlying International Portfolios. The Underlying Equity Portfolios include, among others, funds that invest in either domestic or international equity securities of small, medium and/or large capitalization companies and the Underlying Fixed Income Portfolios include, among others, funds that invest in domestic government and corporate bonds. The Underlying Portfolios will generally be limited to index funds, which are passively managed to track the performance of designated indices, although the Portfolio may also from time to time invest in Underlying Portfolios that are not index funds, including for cash management purposes. The Portfolio may invest a significant portion of its assets in any single Underlying Portfolio. The following chart sets forth the Portfolio’s target allocations set by SunAmerica on January 31, 2026 to the Underlying Equity Portfolios and Underlying Fixed Income Portfolios. The Portfolio’s actual allocations may vary from these projections and will fluctuate from time to time due to, among other things, market conditions and changes made by the Adviser to the target allocations.Underlying Portfolio% of TotalPortfolioEquity92.00%SA Large Cap Index Portfolio34.00%SA Mid Cap Index Portfolio8.00%SA Small Cap Index Portfolio5.00%SA International Index Portfolio40.00%SA Emerging Markets Equity Index Portfolio5.00%Fixed Income8.00%SA Fixed Income Intermediate Index Portfolio4.00%SA Fixed Income Index Portfolio4.00%The Underlying Portfolio selection is made based on the Portfolio’s particular asset allocation strategy discussed above. The Adviser may adjust the Portfolio’s allocation to the Underlying Portfolios from time to time as it deems necessary, including based on market conditions or other factors. The Adviser intends to rebalance the Portfolio on an ongoing basis using cash flows; however, it reserves the right to rebalance the Portfolio through exchanges at any time.

SA Global Index Allocation 90-10 Portfolio Investment Strategy - SA Global Index Allocation 90-10 Portfolio

Dec. 31, 2025

<span style="color:#000000;font-family:Arial;font-size:12pt;font-style:italic;font-weight:bold;">Principal Investment Strategies of the Portfolio</span>

Strategy Narrative [Text Block]

The Portfolio is structured as a “fund-of-funds,” which means that it pursues its investment goal by investing its assets in a combination of other mutual funds (the “Underlying Portfolios”). The Underlying Portfolios will primarily include other funds in the Trust but may also include other funds advised by the Adviser. Under normal circumstances, the Portfolio will seek to allocate 90% of its assets (with a range of 80% to 100%) to Underlying Portfolios investing primarily in equity securities (“Underlying Equity Portfolios”) and 10% of its assets (with a range of 0% to 20%) to Underlying Portfolios investing primarily in fixed income securities (“Underlying Fixed Income Portfolios”). The Underlying Portfolios invest in, or obtain exposure to, equity or fixed income securities of U.S. or foreign corporate and governmental issuers. Certain Underlying Equity Portfolios invest in, or obtain exposure to, investments in a number of different countries around the world, which may include emerging markets (“Underlying International Portfolios”). Under normal circumstances, the Portfolio invests approximately half of its allocation to Underlying Equity Portfolios in Underlying International Portfolios. The Underlying Equity Portfolios include, among others, funds that invest in either domestic or international equity securities of small, medium and/or large capitalization companies and the Underlying Fixed Income Portfolios include, among others, funds that invest in domestic government and corporate bonds. The Underlying Portfolios will generally be limited to index funds, which are passively managed to track the performance of designated indices, although the Portfolio may also from time to time invest in Underlying Portfolios that are not index funds, including for cash management purposes. The Portfolio may invest a significant portion of its assets in any single Underlying Portfolio. The following chart sets forth the Portfolio’s target allocations set by SunAmerica on January 31, 2026 to the Underlying Equity Portfolios and Underlying Fixed Income Portfolios. The Portfolio’s actual allocations may vary from these projections and will fluctuate from time to time due to, among other things, market conditions and changes made by the Adviser to the target allocations.Underlying Portfolio% of TotalPortfolioEquity92.00%SA Large Cap Index Portfolio34.00%SA Mid Cap Index Portfolio8.00%SA Small Cap Index Portfolio5.00%SA International Index Portfolio40.00%SA Emerging Markets Equity Index Portfolio5.00%Fixed Income8.00%SA Fixed Income Intermediate Index Portfolio4.00%SA Fixed Income Index Portfolio4.00%The Underlying Portfolio selection is made based on the Portfolio’s particular asset allocation strategy discussed above. The Adviser may adjust the Portfolio’s allocation to the Underlying Portfolios from time to time as it deems necessary, including based on market conditions or other factors. The Adviser intends to rebalance the Portfolio on an ongoing basis using cash flows; however, it reserves the right to rebalance the Portfolio through exchanges at any time.