Shareholder Report, Average Annual Return (Details)
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12 Months Ended |
60 Months Ended |
89 Months Ended |
90 Months Ended |
120 Months Ended |
Mar. 31, 2026 |
Mar. 31, 2026 |
Mar. 31, 2026 |
Mar. 31, 2026 |
Mar. 31, 2026 |
| C000202747 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class W Shares at NAV
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| Average Annual Return, Percent |
4.77%
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0.98%
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2.76%
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| C000033991 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Retirement Class Shares at NAV
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| Average Annual Return, Percent |
4.33%
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0.45%
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1.99%
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| C000014635 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class R6 Shares at NAV
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| Average Annual Return, Percent |
4.48%
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0.69%
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2.24%
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| C000079556 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Premier Class Shares at NAV
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| Average Annual Return, Percent |
4.44%
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0.56%
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2.08%
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| C000162549 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
4.33%
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0.55%
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2.13%
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| C000033992 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
0.35%
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(0.36%)
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1.55%
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| C000202755 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class W Shares at NAV
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| Average Annual Return, Percent |
4.78%
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3.11%
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3.28%
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| C000033275 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Retirement Class Shares at NAV
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| Average Annual Return, Percent |
4.25%
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2.57%
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2.37%
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| C000033276 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class R6 Shares at NAV
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| Average Annual Return, Percent |
4.51%
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2.82%
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2.62%
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| C000079571 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Premier Class Shares at NAV
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| Average Annual Return, Percent |
4.35%
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2.67%
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2.47%
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| C000162566 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
4.37%
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2.75%
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2.56%
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| C000033274 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
1.56%
|
2.01%
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2.06%
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| C000033277 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
2.04%
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3.09%
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4.81%
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| C000162567 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
7.36%
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4.27%
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5.49%
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| C000079572 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Premier Class Shares at NAV
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| Average Annual Return, Percent |
7.35%
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4.27%
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5.47%
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| C000033279 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class R6 Shares at NAV
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| Average Annual Return, Percent |
7.51%
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4.40%
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5.62%
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| C000033278 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Retirement Class Shares at NAV
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| Average Annual Return, Percent |
7.25%
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4.15%
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5.35%
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| C000202756 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class W Shares at NAV
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| Average Annual Return, Percent |
7.90%
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4.77%
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4.99%
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| C000202758 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class W Shares at NAV
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| Average Annual Return, Percent |
4.79%
|
1.25%
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3.00%
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| C000033284 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Retirement Class Shares at NAV
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| Average Annual Return, Percent |
4.23%
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0.68%
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2.27%
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| C000033285 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class R6 Shares at NAV
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| Average Annual Return, Percent |
4.49%
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0.95%
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2.53%
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| C000079574 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Premier Class Shares at NAV
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| Average Annual Return, Percent |
4.33%
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0.77%
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2.37%
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| C000162569 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
4.41%
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0.85%
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2.45%
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| C000033283 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
0.24%
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(0.14%)
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1.81%
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| C000033286 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
1.00%
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(0.31%)
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1.30%
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| C000162570 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
4.41%
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0.50%
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1.81%
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| C000033287 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class R6 Shares at NAV
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| Average Annual Return, Percent |
4.45%
|
0.58%
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1.88%
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| C000202762 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class W Shares at NAV
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| Average Annual Return, Percent |
4.39%
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0.31%
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2.07%
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| C000079523 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class R6 Shares at NAV
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| Average Annual Return, Percent |
4.32%
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0.25%
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1.58%
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| C000079524 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Retirement Class Shares at NAV
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| Average Annual Return, Percent |
4.06%
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0.01%
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1.34%
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| C000079525 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Premier Class Shares at NAV
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| Average Annual Return, Percent |
4.17%
|
0.10%
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1.43%
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| C000162579 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
4.22%
|
0.15%
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1.48%
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| C000079526 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
0.05%
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(0.82%)
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0.88%
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| C000117723 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
0.70%
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(0.51%)
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1.41%
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| C000162598 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
4.68%
|
0.46%
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1.99%
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| C000117722 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Premier Class Shares at NAV
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| Average Annual Return, Percent |
4.70%
|
0.35%
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1.91%
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| C000117721 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class R6 Shares at NAV
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| Average Annual Return, Percent |
4.86%
|
0.52%
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2.07%
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| C000117724 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Retirement Class Shares at NAV
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| Average Annual Return, Percent |
4.60%
|
0.27%
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1.81%
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| C000202767 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class W Shares at NAV
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| Average Annual Return, Percent |
3.96%
|
2.08%
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2.51%
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| C000158753 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Retirement Class Shares at NAV
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| Average Annual Return, Percent |
3.64%
|
1.75%
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1.67%
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| C000158750 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class R6 Shares at NAV
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| Average Annual Return, Percent |
3.89%
|
2.00%
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1.93%
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| C000158751 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Premier Class Shares at NAV
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| Average Annual Return, Percent |
3.72%
|
1.83%
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1.75%
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| C000162603 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
3.87%
|
1.87%
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1.81%
|
| C000158752 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
1.05%
|
1.15%
|
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|
1.33%
|
| C000205813 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
0.29%
|
(0.31%)
|
1.83%
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| C000205815 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
4.40%
|
0.70%
|
2.60%
|
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| C000205812 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Premier Class Shares at NAV
|
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| Average Annual Return, Percent |
4.33%
|
0.63%
|
2.51%
|
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| C000205811 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class R6 Shares at NAV
|
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| Average Annual Return, Percent |
4.49%
|
0.78%
|
2.66%
|
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| C000205814 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Retirement Class Shares at NAV
|
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| Average Annual Return, Percent |
4.23%
|
0.55%
|
2.47%
|
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| C000205819 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Retirement Class Shares at NAV
|
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| Average Annual Return, Percent |
4.35%
|
2.31%
|
2.83%
|
|
|
| C000205816 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class R6 Shares at NAV
|
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| Average Annual Return, Percent |
4.60%
|
2.56%
|
3.08%
|
|
|
| C000205817 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Premier Class Shares at NAV
|
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|
|
|
| Average Annual Return, Percent |
4.54%
|
2.43%
|
2.94%
|
|
|
| C000205820 [Member] |
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| Average Annual Return [Line Items] |
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|
|
| Line Graph and Table Measure Name |
Class I Shares at NAV
|
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|
|
|
| Average Annual Return, Percent |
4.45%
|
2.50%
|
3.03%
|
|
|
| C000205818 [Member] |
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| Average Annual Return [Line Items] |
|
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|
|
| Line Graph and Table Measure Name |
Class A at maximum sales charge (Offering Price)
|
|
|
|
|
| Average Annual Return, Percent |
1.64%
|
1.76%
|
2.43%
|
|
|
| Without Sales Load [Member] | C000033992 [Member] |
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| Average Annual Return [Line Items] |
|
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|
|
|
| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
|
|
|
|
|
| Average Annual Return, Percent |
4.26%
|
0.40%
|
|
|
1.94%
|
| Without Sales Load [Member] | C000033274 [Member] |
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|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
|
|
|
|
|
| Average Annual Return, Percent |
4.17%
|
2.52%
|
|
|
2.32%
|
| Without Sales Load [Member] | C000033277 [Member] |
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|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
|
|
|
|
|
| Average Annual Return, Percent |
7.17%
|
4.11%
|
|
|
5.32%
|
| Without Sales Load [Member] | C000033283 [Member] |
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|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
|
|
|
|
|
| Average Annual Return, Percent |
4.14%
|
0.62%
|
|
|
2.20%
|
| Without Sales Load [Member] | C000033286 [Member] |
|
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|
| Average Annual Return [Line Items] |
|
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|
|
|
| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
|
|
|
|
|
| Average Annual Return, Percent |
4.15%
|
0.31%
|
|
|
1.60%
|
| Without Sales Load [Member] | C000079526 [Member] |
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|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
|
|
|
|
|
| Average Annual Return, Percent |
3.98%
|
(0.07%)
|
|
|
1.26%
|
| Without Sales Load [Member] | C000117723 [Member] |
|
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|
|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
|
|
|
|
|
| Average Annual Return, Percent |
4.63%
|
0.26%
|
|
|
1.79%
|
| Without Sales Load [Member] | C000158752 [Member] |
|
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|
|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
|
|
|
|
|
| Average Annual Return, Percent |
3.67%
|
1.67%
|
|
|
1.59%
|
| Without Sales Load [Member] | C000205813 [Member] |
|
|
|
|
|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
|
|
|
|
|
| Average Annual Return, Percent |
4.14%
|
0.45%
|
2.35%
|
|
|
| Without Sales Load [Member] | C000205818 [Member] |
|
|
|
|
|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
|
|
|
|
|
| Average Annual Return, Percent |
4.26%
|
2.27%
|
2.79%
|
|
|
| Bloomberg U S Aggregate Bond Index [Member] |
|
|
|
|
|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Bloomberg U.S. Aggregate Bond Index
|
|
|
|
|
| Average Annual Return, Percent |
4.35%
|
0.31%
|
2.15%
|
2.07%
|
1.70%
|
| Bloomberg Municipal Bond Index [Member] |
|
|
|
|
|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Bloomberg Municipal Bond Index
|
|
|
|
|
| Average Annual Return, Percent |
4.29%
|
0.84%
|
|
|
2.16%
|
| Bloomberg U S 1 3 Year Government Credit Bond Index [Member] |
|
|
|
|
|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Bloomberg U.S. 1‑3 Year Government/Credit Bond Index
|
|
|
|
|
| Average Annual Return, Percent |
3.96%
|
2.04%
|
2.49%
|
2.49%
|
2.02%
|
| ICE BofA BB B U S Cash Pay High Yield Constrained Index [Member] |
|
|
|
|
|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
ICE BofA BB‑B U.S. Cash Pay High Yield Constrained Index
|
|
|
|
|
| Average Annual Return, Percent |
7.04%
|
3.95%
|
|
4.90%
|
5.67%
|
| Bloomberg 10 Year Municipal Bond Index [Member] |
|
|
|
|
|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Bloomberg 10‑Year Municipal Bond Index
|
|
|
|
|
| Average Annual Return, Percent |
4.81%
|
1.00%
|
|
|
2.26%
|
| Bloomberg MSCI U S Green Bond Index [Member] |
|
|
|
|
|
| Average Annual Return [Line Items] |
|
|
|
|
|
| Line Graph and Table Measure Name |
Bloomberg MSCI U.S. Green Bond Index
|
|
|
|
|
| Average Annual Return, Percent |
4.66%
|
0.95%
|
2.80%
|
|
|