SA Index Allocation 80-20 Portfolio Investment Strategy - SA Index Allocation 80-20 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 80% of its assets (with a range of 70% to 90%) to Underlying Portfolios investing primarily in equity securities (“Underlying Equity Portfolios”) and 20% of its assets (with a range of 10% to 30%) to Underlying Portfolios investing primarily in fixed income securities (“Underlying Fixed Income Portfolios”). The Underlying Equity Portfolios include, among others, funds that invest in domestic and 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 Asset Management, LLC (“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 TotalPortfolioEquity82.00%SA Large Cap Index Portfolio51.90%SA Mid Cap Index Portfolio10.10%SA Small Cap Index Portfolio5.00%SA International Index Portfolio15.00%Fixed Income18.00%SA Fixed Income Intermediate Index Portfolio9.00%SA Fixed Income Index Portfolio9.00%The Underlying Portfolio selection is made based on the Portfolio’s particular asset allocation strategy. 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 Index Allocation 80-20 Portfolio Investment Strategy - SA Index Allocation 80-20 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 80% of its assets (with a range of 70% to 90%) to Underlying Portfolios investing primarily in equity securities (“Underlying Equity Portfolios”) and 20% of its assets (with a range of 10% to 30%) to Underlying Portfolios investing primarily in fixed income securities (“Underlying Fixed Income Portfolios”). The Underlying Equity Portfolios include, among others, funds that invest in domestic and 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 Asset Management, LLC (“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 TotalPortfolioEquity82.00%SA Large Cap Index Portfolio51.90%SA Mid Cap Index Portfolio10.10%SA Small Cap Index Portfolio5.00%SA International Index Portfolio15.00%Fixed Income18.00%SA Fixed Income Intermediate Index Portfolio9.00%SA Fixed Income Index Portfolio9.00%The Underlying Portfolio selection is made based on the Portfolio’s particular asset allocation strategy. 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.