Shareholder Report, Holdings (Details)	May 31, 2025
C000012163 [Member] \| Corporate Bond Securities [Member]
Holdings [Line Items]
Percent of Net Asset Value	21.30%
C000012163 [Member] \| Taxable Municipal Bonds [Member]
Holdings [Line Items]
Percent of Net Asset Value	1.40%
C000012163 [Member] \| US Government Corporations and Agencies Securities [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.30%
C000012163 [Member] \| Sovereign Debt [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.60%
C000012163 [Member] \| Common Stock [Member]
Holdings [Line Items]
Percent of Net Asset Value	66.10%
C000012163 [Member] \| Asset Backed Commercial Mortgage Backed Securities [Member]
Holdings [Line Items]
Percent of Net Asset Value	1.10%
C000012163 [Member] \| Other Assets and Liabilities Net [Member]
Holdings [Line Items]
Percent of Net Asset Value	1.20%
C000012164 [Member] \| Corporate Bond Securities [Member]
Holdings [Line Items]
Percent of Net Asset Value	21.30%
C000012164 [Member] \| Taxable Municipal Bonds [Member]
Holdings [Line Items]
Percent of Net Asset Value	1.40%
C000012164 [Member] \| US Government Corporations and Agencies Securities [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.30%
C000012164 [Member] \| Sovereign Debt [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.60%
C000012164 [Member] \| Common Stock [Member]
Holdings [Line Items]
Percent of Net Asset Value	66.10%
C000012164 [Member] \| Asset Backed Commercial Mortgage Backed Securities [Member]
Holdings [Line Items]
Percent of Net Asset Value	1.10%
C000012164 [Member] \| Other Assets and Liabilities Net [Member]
Holdings [Line Items]
Percent of Net Asset Value	1.20%