000001 - Document - Document and Entity Information link:presentationLink link:definitionLink link:calculationLink 020000 - Document - Risk/Return Summary {Unlabeled} - U.S. Government Securities Fund® link:presentationLink link:definitionLink link:calculationLink 020001 - Schedule - Shareholder Fees link:presentationLink link:definitionLink link:calculationLink 020002 - Schedule - Annual Fund Operating Expenses link:presentationLink link:definitionLink link:calculationLink 020003 - Schedule - Expense Example link:presentationLink link:definitionLink link:calculationLink 020004 - Schedule - Expense Example No Redemption link:presentationLink link:definitionLink link:calculationLink 020005 - Schedule - Annual Total Returns [Bar Chart] link:presentationLink link:definitionLink link:calculationLink 020006 - Schedule - Average Annual Returns {Transposed} link:presentationLink link:definitionLink link:calculationLink 020007 - Disclosure - Risk/Return Detail Data {Elements} - U.S. Government Securities Fund® link:presentationLink link:definitionLink link:calculationLink