Load [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 120 Months Ended | ||
|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
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| Bloomberg Municipal Bond Index (Index reflects no deduction for fees, expenses or taxes) | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 4.25% | 0.80% | 2.34% | ||
| North Carolina Tax-Free Income Series | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 3.77% | 0.11% | 1.66% | ||
| North Carolina Tax-Free Income Series | After Taxes on Distributions | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 3.77% | 0.11% | 1.66% | ||
| North Carolina Tax-Free Income Series | After Taxes on Distributions and Sales | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | [1] | 3.45% | 0.63% | 1.84% | |
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