SA American Century Inflation Protection Portfolio Investment Strategy - SA American Century Inflation Protection Portfolio	Mar. 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 invests substantially all of its assets in investment-grade debt securities. To help protect against U.S. inflation, under normal conditions the Portfolio will invest over 50% of its assets in inflation-indexed debt securities. These securities include inflation-indexed U.S. Treasury securities, inflation-indexed securities issued by U.S. government agencies and instrumentalities other than the U.S. Treasury, and inflation-indexed securities issued by other entities such as U.S. and non-U.S. corporations and foreign governments. Inflation-indexed securities are designed to protect the future purchasing power of the money invested in them. The Portfolio also may invest in debt securities that are not inflation-indexed. Such investments could include other investment-grade debt securities (e.g., corporate bonds and notes), commercial paper, and mortgage-backed and asset-backed securities, whether issued by the U.S. government, its agencies or instrumentalities, U.S. and non-U.S. corporations or other non-governmental issuers, or foreign governments.Securities issued by the U.S. Treasury and certain U.S. government agencies, such as the Government National Mortgage Association, are supported by the full faith and credit of the U.S. government. Securities issued by other U.S. government agencies, such as the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and the Federal Home Loan Bank are not guaranteed by the U.S. Treasury or supported by the full faith and credit of the U.S. government. However, these agencies are authorized to borrow from the U.S. Treasury to meet their obligations. Inflation-indexed securities issued by non-U.S. government entities are backed only by the credit of the issuer.The Portfolio also may invest in derivative instruments, provided that such instruments are in keeping with the Portfolio’s investment goal. For example, the Portfolio could use swap agreements to manage or reduce the risk of the effects of inflation with respect to the Portfolio’s position in non-inflation-indexed securities. The Portfolio also may enter into foreign currency exchange transactions for hedging purposes or to enhance returns. The Portfolio may also use when-issued and forward commitment transactions. The Portfolio may also invest in collateralized debt obligations (“CDOs”), including collateralized loan obligations, and other similarly structured investments.The portfolio managers are not limited to a specific weighted average maturity range. However, the portfolio managers monitor the Portfolio’s weighted average maturity and seek to adjust it as appropriate, taking into account market conditions, the current inflation rate and other relevant factors.

SA American Century Inflation Protection Portfolio Investment Strategy - SA American Century Inflation Protection Portfolio

Mar. 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 invests substantially all of its assets in investment-grade debt securities. To help protect against U.S. inflation, under normal conditions the Portfolio will invest over 50% of its assets in inflation-indexed debt securities. These securities include inflation-indexed U.S. Treasury securities, inflation-indexed securities issued by U.S. government agencies and instrumentalities other than the U.S. Treasury, and inflation-indexed securities issued by other entities such as U.S. and non-U.S. corporations and foreign governments. Inflation-indexed securities are designed to protect the future purchasing power of the money invested in them. The Portfolio also may invest in debt securities that are not inflation-indexed. Such investments could include other investment-grade debt securities (e.g., corporate bonds and notes), commercial paper, and mortgage-backed and asset-backed securities, whether issued by the U.S. government, its agencies or instrumentalities, U.S. and non-U.S. corporations or other non-governmental issuers, or foreign governments.Securities issued by the U.S. Treasury and certain U.S. government agencies, such as the Government National Mortgage Association, are supported by the full faith and credit of the U.S. government. Securities issued by other U.S. government agencies, such as the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and the Federal Home Loan Bank are not guaranteed by the U.S. Treasury or supported by the full faith and credit of the U.S. government. However, these agencies are authorized to borrow from the U.S. Treasury to meet their obligations. Inflation-indexed securities issued by non-U.S. government entities are backed only by the credit of the issuer.The Portfolio also may invest in derivative instruments, provided that such instruments are in keeping with the Portfolio’s investment goal. For example, the Portfolio could use swap agreements to manage or reduce the risk of the effects of inflation with respect to the Portfolio’s position in non-inflation-indexed securities. The Portfolio also may enter into foreign currency exchange transactions for hedging purposes or to enhance returns. The Portfolio may also use when-issued and forward commitment transactions. The Portfolio may also invest in collateralized debt obligations (“CDOs”), including collateralized loan obligations, and other similarly structured investments.The portfolio managers are not limited to a specific weighted average maturity range. However, the portfolio managers monitor the Portfolio’s weighted average maturity and seek to adjust it as appropriate, taking into account market conditions, the current inflation rate and other relevant factors.