Label Element Value
Risk/Return: rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName NORTH CAROLINA CAPITAL MANAGEMENT TRUST
Prospectus Date rr_ProspectusDate Aug. 29, 2019
06.30 North Carolina Capital Management Trust Combo PRO-09 | Government Portfolio  
Risk/Return: rr_RiskReturnAbstract  
Supplement to Prospectus [Text Block] rr_SupplementToProspectusTextBlock

Supplement to the
The North Carolina Capital Management Trust:
Government Portfolio and Term Portfolio
August 29, 2019
Prospectus
Operating Expenses Caption [Text] rr_OperatingExpensesCaption <p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Annual Operating Expenses</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">(expenses that you pay each year as a % of the value of your investment)</p>
06.30 North Carolina Capital Management Trust Combo PRO-09 | Government Portfolio | Government Portfolio (NCCMT)-Default  
Risk/Return: rr_RiskReturnAbstract  
Management fee (net rate retained by FMR after payment of 12b-1 fees to the distributor) rr_ManagementFeesOverAssets 0.16%
Distribution and/or Service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.07%
Other expenses rr_OtherExpensesOverAssets none
Total annual operating expenses rr_ExpensesOverAssets 0.23% [1]
[1] In order to avoid a negative yield, Fidelity Management & Research Company LLC (FMR) may reimburse expenses or waive fees of Government Portfolio and/or the fund’s distributor may waive all or a portion of the 12b-1 fees of the fund. Any such waivers or expense reimbursement would be voluntary and could be discontinued at any time. There is no guarantee that Government Portfolio will be able to avoid a negative yield.