Shareholder Report, Holdings (Details)	May 31, 2026
C000007976 \| Less than 1 Year
Holdings [Line Items]
Percent of Net Asset Value	6.20%
C000007976 \| 1 to 3 Years
Holdings [Line Items]
Percent of Net Asset Value	2.00%
C000007976 \| 3 to 5 Years
Holdings [Line Items]
Percent of Net Asset Value	1.60%
C000007976 \| 5 to 10 Years
Holdings [Line Items]
Percent of Net Asset Value	12.00%
C000007976 \| 10 to 20 Years
Holdings [Line Items]
Percent of Net Asset Value	45.40%
C000007976 \| 20 to 30 Years
Holdings [Line Items]
Percent of Net Asset Value	31.80%
C000007976 \| Greater than 30 Years
Holdings [Line Items]
Percent of Net Asset Value	1.60%
C000007976 \| Other Line
Holdings [Line Items]
Percent of Net Asset Value	(0.60%)
C000007977 \| Less than 1 Year
Holdings [Line Items]
Percent of Net Asset Value	6.20%
C000007977 \| 1 to 3 Years
Holdings [Line Items]
Percent of Net Asset Value	2.00%
C000007977 \| 3 to 5 Years
Holdings [Line Items]
Percent of Net Asset Value	1.60%
C000007977 \| 5 to 10 Years
Holdings [Line Items]
Percent of Net Asset Value	12.00%
C000007977 \| 10 to 20 Years
Holdings [Line Items]
Percent of Net Asset Value	45.40%
C000007977 \| 20 to 30 Years
Holdings [Line Items]
Percent of Net Asset Value	31.80%
C000007977 \| Greater than 30 Years
Holdings [Line Items]
Percent of Net Asset Value	1.60%
C000007977 \| Other Line
Holdings [Line Items]
Percent of Net Asset Value	(0.60%)