Shareholder Report, Holdings (Details)
|
May 31, 2025 |
C000001498 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
6.10%
|
[1] |
C000001498 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
12.40%
|
[1] |
C000001498 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
11.30%
|
[1] |
C000001498 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
11.60%
|
[1] |
C000001498 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
45.50%
|
[1] |
C000001498 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
13.10%
|
[1] |
C000001498 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000137698 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
6.10%
|
[2] |
C000137698 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
12.40%
|
[2] |
C000137698 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
11.30%
|
[2] |
C000137698 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
11.60%
|
[2] |
C000137698 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
45.50%
|
[2] |
C000137698 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
13.10%
|
[2] |
C000137698 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000001501 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
6.10%
|
[3] |
C000001501 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
12.40%
|
[3] |
C000001501 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
11.30%
|
[3] |
C000001501 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
11.60%
|
[3] |
C000001501 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
45.50%
|
[3] |
C000001501 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
13.10%
|
[3] |
C000001501 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000137697 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
3.40%
|
[4] |
C000137697 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
10.30%
|
[4] |
C000137697 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
10.50%
|
[4] |
C000137697 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
20.50%
|
[4] |
C000137697 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
54.90%
|
[4] |
C000137697 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
0.40%
|
[4] |
C000137697 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000137697 [Member] | Variable Rate Senior Loan Interests [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
0.00%
|
|
C000001497 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
3.40%
|
[5] |
C000001497 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
10.30%
|
[5] |
C000001497 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
10.50%
|
[5] |
C000001497 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
20.50%
|
[5] |
C000001497 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
54.90%
|
[5] |
C000001497 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
0.40%
|
[5] |
C000001497 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000001497 [Member] | Variable Rate Senior Loan Interests [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
0.00%
|
|
C000001490 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
3.90%
|
[6] |
C000001490 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
14.50%
|
[6] |
C000001490 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
5.00%
|
[6] |
C000001490 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
6.70%
|
[6] |
C000001490 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
53.50%
|
[6] |
C000001490 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
16.40%
|
[6] |
C000001490 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000137696 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
3.90%
|
[7] |
C000137696 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
14.50%
|
[7] |
C000137696 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
5.00%
|
[7] |
C000137696 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
6.70%
|
[7] |
C000137696 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
53.50%
|
[7] |
C000137696 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
16.40%
|
[7] |
C000137696 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000001493 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
3.90%
|
[8] |
C000001493 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
14.50%
|
[8] |
C000001493 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
5.00%
|
[8] |
C000001493 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
6.70%
|
[8] |
C000001493 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
53.50%
|
[8] |
C000001493 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
16.40%
|
[8] |
C000001493 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000001494 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
3.40%
|
[9] |
C000001494 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
10.30%
|
[9] |
C000001494 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
10.50%
|
[9] |
C000001494 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
20.50%
|
[9] |
C000001494 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
54.90%
|
[9] |
C000001494 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
0.40%
|
[9] |
C000001494 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000001494 [Member] | Variable Rate Senior Loan Interests [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
0.00%
|
|
C000001489 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
5.00%
|
[10] |
C000001489 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
17.40%
|
[10] |
C000001489 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
15.90%
|
[10] |
C000001489 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
27.40%
|
[10] |
C000001489 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
29.80%
|
[10] |
C000001489 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.50%
|
[10] |
C000001489 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000137695 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
5.00%
|
[11] |
C000137695 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
17.40%
|
[11] |
C000137695 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
15.90%
|
[11] |
C000137695 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
27.40%
|
[11] |
C000137695 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
29.80%
|
[11] |
C000137695 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.50%
|
[11] |
C000137695 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000001486 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
5.00%
|
[12] |
C000001486 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
17.40%
|
[12] |
C000001486 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
15.90%
|
[12] |
C000001486 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
27.40%
|
[12] |
C000001486 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
29.80%
|
[12] |
C000001486 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.50%
|
[12] |
C000001486 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000001474 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
3.30%
|
[13] |
C000001474 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
10.30%
|
[13] |
C000001474 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.80%
|
[13] |
C000001474 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
12.90%
|
[13] |
C000001474 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
60.70%
|
[13] |
C000001474 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
8.00%
|
[13] |
C000001474 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000137693 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
3.30%
|
[14] |
C000137693 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
10.30%
|
[14] |
C000137693 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.80%
|
[14] |
C000137693 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
12.90%
|
[14] |
C000137693 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
60.70%
|
[14] |
C000137693 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
8.00%
|
[14] |
C000137693 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000001477 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
3.30%
|
[15] |
C000001477 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
10.30%
|
[15] |
C000001477 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.80%
|
[15] |
C000001477 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
12.90%
|
[15] |
C000001477 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
60.70%
|
[15] |
C000001477 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
8.00%
|
[15] |
C000001477 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000001478 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
1.40%
|
[16] |
C000001478 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
13.90%
|
[16] |
C000001478 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.20%
|
[16] |
C000001478 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
15.00%
|
[16] |
C000001478 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
61.00%
|
[16] |
C000001478 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.50%
|
[16] |
C000001478 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000137694 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
1.40%
|
[17] |
C000137694 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
13.90%
|
[17] |
C000137694 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.20%
|
[17] |
C000137694 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
15.00%
|
[17] |
C000137694 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
61.00%
|
[17] |
C000137694 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.50%
|
[17] |
C000137694 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
C000001481 [Member] | BB or Lower [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
1.40%
|
[18] |
C000001481 [Member] | N R not rated [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
13.90%
|
[18] |
C000001481 [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.20%
|
[18] |
C000001481 [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
15.00%
|
[18] |
C000001481 [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
61.00%
|
[18] |
C000001481 [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
4.50%
|
[18] |
C000001481 [Member] | Municipal Bonds [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Total Investments |
100.00%
|
|
|
|