Shareholder Report, Holdings (Details)	May 31, 2026
C000007964 \| Less than 1 Year
Holdings [Line Items]
Percent of Net Asset Value	9.50%
C000007964 \| 1 to 3 Years
Holdings [Line Items]
Percent of Net Asset Value	4.20%
C000007964 \| 3 to 5 Years
Holdings [Line Items]
Percent of Net Asset Value	2.70%
C000007964 \| 5 to 10 Years
Holdings [Line Items]
Percent of Net Asset Value	12.80%
C000007964 \| 10 to 20 Years
Holdings [Line Items]
Percent of Net Asset Value	36.10%
C000007964 \| 20 to 30 Years
Holdings [Line Items]
Percent of Net Asset Value	30.70%
C000007964 \| Greater than 30 Years
Holdings [Line Items]
Percent of Net Asset Value	3.30%
C000007964 \| Other Line
Holdings [Line Items]
Percent of Net Asset Value	0.70%
C000007965 \| Less than 1 Year
Holdings [Line Items]
Percent of Net Asset Value	9.50%
C000007965 \| 1 to 3 Years
Holdings [Line Items]
Percent of Net Asset Value	4.20%
C000007965 \| 3 to 5 Years
Holdings [Line Items]
Percent of Net Asset Value	2.70%
C000007965 \| 5 to 10 Years
Holdings [Line Items]
Percent of Net Asset Value	12.80%
C000007965 \| 10 to 20 Years
Holdings [Line Items]
Percent of Net Asset Value	36.10%
C000007965 \| 20 to 30 Years
Holdings [Line Items]
Percent of Net Asset Value	30.70%
C000007965 \| Greater than 30 Years
Holdings [Line Items]
Percent of Net Asset Value	3.30%
C000007965 \| Other Line
Holdings [Line Items]
Percent of Net Asset Value	0.70%