v3.26.1
S000019579 [Member] Expense Example - World Selection Index Fund
Mar. 31, 2026
USD ($)
Class K  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 25
Expense Example, with Redemption, 3 Years 77
Expense Example, with Redemption, 5 Years 135
Expense Example, with Redemption, 10 Years 306
Class I  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 30
Expense Example, with Redemption, 3 Years 93
Expense Example, with Redemption, 5 Years 163
Expense Example, with Redemption, 10 Years $ 368