v3.26.1
Shareholder Report
 6 Months Ended
May 31, 2026
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, 2026
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, 2025 to May 31, 2026.
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 
$ 23 
0.45%
  
Expenses Paid, Amount $ 23
Expense Ratio, Percent 0.45%
Net Assets $ 729,882,792
Holdings Count | shares 316
Investment Company Portfolio Turnover 7.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of May 31, 2026)
 
KEY FACTS 
  
  
Fund Size
$729,882,792
  
Number of Holdings
316
  
Portfolio Turnover
7%
  
Holdings [Text Block]   REVENUE SOURCES (% of Fund's net assets) General Obligations 37.0   Transportation 23.1   Education 16.0   Housing 7.4   Health Care 5.0   Others(Individually Less Than 5%) 5.9   94.4       AAA 1.9 AA 35.2 A 45.6 BBB 8.3 BB 1.1 Not Rated 2.3 Short-Term Investments and Net Other Assets (Liabilities) 5.6 QUALITY DIVERSIFICATION (% of Fund's net assets)     AAA - 1.9                                  AA - 35.2                                  A - 45.6                                   BBB - 8.3                                  BB - 1.1                                   Not Rated - 2.3                            Short-Term Investments and Net Other Assets (Liabilities) - 5.6   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, 2025 to May 31, 2026.
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 
$ 24 
0.47%
  
Expenses Paid, Amount $ 24
Expense Ratio, Percent 0.47%
Net Assets $ 370,112,558
Holdings Count | shares 261
Investment Company Portfolio Turnover 2.00%
Additional Fund Statistics [Text Block] Key Fund Statistics
(as of May 31, 2026)
 
KEY FACTS 
  
  
Fund Size
$370,112,558
  
Number of Holdings
261
  
Portfolio Turnover
2%
  
Holdings [Text Block]   REVENUE SOURCES (% of Fund's net assets) General Obligations 43.3   Education 16.9   Health Care 12.6   Special Tax 11.1   Housing 6.5   Others(Individually Less Than 5%) 5.2   95.6       AAA 8.7 AA 47.6 A 24.1 BBB 9.5 BB 2.7 Not Rated 3.0 Short-Term Investments and Net Other Assets (Liabilities) 4.4 QUALITY DIVERSIFICATION (% of Fund's net assets)     AAA - 8.7                                  AA - 47.6                                  A - 24.1                                   BBB - 9.5                                  BB - 2.7                                   Not Rated - 3.0                            Short-Term Investments and Net Other Assets (Liabilities) - 4.4   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.