S000001247 [Member] Expense Example - STOCK INDEX FUND - STOCK INDEX FUND	Mar. 31, 2026 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 5
Expense Example, with Redemption, 3 Years	25
Expense Example, with Redemption, 5 Years	47
Expense Example, with Redemption, 10 Years	$ 111

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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