| Form N-CSR Cover | 12 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | The North Carolina Capital Management Trust |
| Entity Central Index Key | 0000702149 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 12 Months Ended |
| Jun. 30, 2024 USD ($) shares | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | The North Carolina Capital Management Trust |
| Entity Central Index Key | 0000702149 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| North Carolina Capital Management Trust - Government Portfolio | |
| Shareholder Report [Line Items] | |
| Fund Name | Government Portfolio |
| Class Name | Government Portfolio |
| Trading Symbol | NCCTX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Government Portfolio for the period July 1, 2023 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-222-3232. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1-800-222-3232 |
| Additional Information Website | fundresearch.fidelity.com/prospectus/sec |
| Expenses [Text Block] | What were your Fund costs for the last year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Government Portfolio $ 0.14 % |
| Expenses Paid, Amount | $ 14 |
| Expense Ratio, Percent | 0.14% |
| Net Assets | $ 20,603,345,239 |
| Holdings Count | shares | 289 |
| Advisory Fees Paid, Amount | $ 40,152,360 |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 289 Total Advisory Fee $ |
| Holdings [Text Block] | EFFECTIVE MATURITY DIVERSIFICATION (% of Fund's net assets) Days 1-7 42.7 8-30 29.9 31-60 11.7 61-90 5.9 91-180 8.0 >180 2.5 U.S. Treasury Obligations 65.6 U.S. Government Agency - Debt 31.2 Repurchase Agreements 3.9 ASSET ALLOCATION (% of Fund's net assets) Net Other Assets (Liabilities) - (0.7)% |
| Material Fund Change [Text Block] | How has the Fund changed? This is a summary of certain changes to the Fund since July 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by August 29, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-222-3232 . The fund's principal investment risks were updated in connection with the implementation of recent rule amendments related to money market funds adopted by the SEC. |
| Material Fund Change Risks Change [Text Block] | The fund's principal investment risks were updated in connection with the implementation of recent rule amendments related to money market funds adopted by the SEC. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since July 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by August 29, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-222-3232 . |
| Updated Prospectus Phone Number | 1-800-222-3232</span>" id="sjs-B32"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-800-222-3232</span> |
| Updated Prospectus Web Address | fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B33"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec</span> |
| Shareholder Report, Holdings (Details) - North Carolina Capital Management Trust - Government Portfolio | Jun. 30, 2024 |
| EMD0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 42.70% |
| EMD1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 29.90% |
| EMD2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.70% |
| EMD3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.90% |
| EMD4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8% |
| EMD5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.50% |
| AAUSTreasuryObligationsMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 65.60% |
| AAUSGovernmentAgencyDebtMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 31.20% |
| AARepurchaseAgreementsMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.90% |
