| Form N-CSR Cover | 6 Months Ended |
| May 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | Fidelity Court Street Trust |
| Entity Central Index Key | 0000225323 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | May 31, 2024 |
| Shareholder Report | 6 Months Ended |
| May 31, 2024 USD ($) shares | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | Fidelity Court Street Trust |
| Entity Central Index Key | 0000225323 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | May 31, 2024 |
| Fidelity New Jersey Municipal Income Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® New Jersey Municipal Income Fund |
| Class Name | Fidelity® New Jersey Municipal Income Fund |
| Trading Symbol | FNJHX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains information about Fidelity® New Jersey Municipal Income Fund for the period December 1, 2023 to May 31, 2024. |
| Shareholder Report Annual or Semi-Annual | semi-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 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com. |
| Additional Information Phone Number | 1-800-544-8544 |
| Additional Information Email | fidfunddocuments@fidelity.com |
| Additional Information Website | fundresearch.fidelity.com/prospectus/sec |
| Expenses [Text Block] | What were your Fund costs for the last six months? (based on hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® New Jersey Municipal Income Fund $ 0.46 % |
| Expenses Paid, Amount | $ 23 |
| Expense Ratio, Percent | 0.46% |
| Net Assets | $ 522,425,502 |
| Holdings Count | shares | 242 |
| Investment Company Portfolio Turnover | 16% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of May 31, 2024) KEY FACTS Fund Size $ Number of Holdings 242 Portfolio Turnover 16 % |
| Holdings [Text Block] | REVENUE SOURCES (% of Fund's net assets) General Obligations 33.1 Transportation 20.2 Education 18.0 Health Care 13.1 Others(Individually Less Than 5%) 15.6 100.0 AAA 3.3 AA 32.7 A 42.8 BBB 11.9 Not Rated 3.9 Short-Term Investments and Net Other Assets (Liabilities) 5.4 QUALITY DIVERSIFICATION (% of Fund's net assets) We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes. |
| Fidelity Connecticut Municipal Income Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® Connecticut Municipal Income Fund |
| Class Name | Fidelity® Connecticut Municipal Income Fund |
| Trading Symbol | FICNX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains information about Fidelity® Connecticut Municipal Income Fund for the period December 1, 2023 to May 31, 2024. |
| Shareholder Report Annual or Semi-Annual | semi-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 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com. |
| Additional Information Phone Number | 1-800-544-8544 |
| Additional Information Email | fidfunddocuments@fidelity.com |
| Additional Information Website | fundresearch.fidelity.com/prospectus/sec |
| Expenses [Text Block] | What were your Fund costs for the last six months? (based on hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Connecticut Municipal Income Fund $ 0.49 % |
| Expenses Paid, Amount | $ 24 |
| Expense Ratio, Percent | 0.49% |
| Net Assets | $ 288,487,062 |
| Holdings Count | shares | 212 |
| Investment Company Portfolio Turnover | 19% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of May 31, 2024) KEY FACTS Fund Size $ Number of Holdings 212 Portfolio Turnover 19 % |
| Holdings [Text Block] | REVENUE SOURCES (% of Fund's net assets) General Obligations 45.8 Education 16.8 Health Care 16.7 Housing 7.8 Special Tax 7.4 Others(Individually Less Than 5%) 5.5 100.0 AAA 10.5 AA 39.6 A 26.0 BBB 13.5 BB 3.4 Not Rated 4.7 Short-Term Investments and Net Other Assets (Liabilities) 2.3 QUALITY DIVERSIFICATION (% of Fund's net assets) We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes. |
| Shareholder Report, Holdings (Details) | May 31, 2024 |
| Fidelity New Jersey Municipal Income Fund | RS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 33.10% |
| Fidelity New Jersey Municipal Income Fund | RS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 20.20% |
| Fidelity New Jersey Municipal Income Fund | RS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 18% |
| Fidelity New Jersey Municipal Income Fund | RS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.10% |
| Fidelity New Jersey Municipal Income Fund | RS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 15.60% |
| Fidelity New Jersey Municipal Income Fund | QDAMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 42.80% |
| Fidelity New Jersey Municipal Income Fund | QDBBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.90% |
| Fidelity New Jersey Municipal Income Fund | QDNotRatedMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.90% |
| Fidelity New Jersey Municipal Income Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.40% |
| Fidelity Connecticut Municipal Income Fund | RS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 45.80% |
| Fidelity Connecticut Municipal Income Fund | RS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 16.80% |
| Fidelity Connecticut Municipal Income Fund | RS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 16.70% |
| Fidelity Connecticut Municipal Income Fund | RS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.80% |
| Fidelity Connecticut Municipal Income Fund | RS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.40% |
| Fidelity Connecticut Municipal Income Fund | RS5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.50% |
| Fidelity Connecticut Municipal Income Fund | QDAMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 26% |
| Fidelity Connecticut Municipal Income Fund | QDBBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.50% |
| Fidelity Connecticut Municipal Income Fund | QDNotRatedMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.70% |
| Fidelity Connecticut Municipal Income Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.30% |
| Fidelity Connecticut Municipal Income Fund | QDBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.40% |
| Label | Element | Value |
| C000016602 [Member] | QDAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 39.60% |
| C000016602 [Member] | QDAAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 10.50% |
| C000016604 [Member] | QDAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 32.70% |
| C000016604 [Member] | QDAAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 3.30% |
