S000001259 [Member] Expense Example - LIMITED TERM U.S. GOVERNMENT FUND - LIMITED TERM U.S. GOVERNMENT FUND	Mar. 31, 2026 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 45
Expense Example, with Redemption, 3 Years	211
Expense Example, with Redemption, 5 Years	391
Expense Example, with Redemption, 10 Years	$ 912

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Form N-1A
-Section 3
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
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