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S000011985 [Member] Investment Objectives and Goals - BATS: Interest Rate Hedge Series
Mar. 31, 2026
Prospectus [Line Items]  
Risk/Return [Heading] Fund Overview Key Facts About BATS: Interest Rate Hedge Series
Objective [Heading] Investment Objective
Objective, Primary [Text Block]
The investment objective of the BATS: Interest Rate Hedge Series (formerly known as BATS: Series P Portfolio) (the “Fund”) is to seek to provide a duration that is the inverse of its benchmark.