v3.26.1
Expense Example
Mar. 31, 2026
USD ($)
Eaton Vance National Ultra-Short Municipal Income Fund | Eaton Vance National Ultra-Short Municipal Income Fund | Advisers Class  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 51
Expense Example, with Redemption, 3 Years 178
Expense Example, with Redemption, 5 Years 316
Expense Example, with Redemption, 10 Years 718
Eaton Vance National Ultra-Short Municipal Income Fund | Eaton Vance National Ultra-Short Municipal Income Fund | Class A  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 275
Expense Example, with Redemption, 3 Years 399
Expense Example, with Redemption, 5 Years 534
Expense Example, with Redemption, 10 Years 927
Eaton Vance National Ultra-Short Municipal Income Fund | Eaton Vance National Ultra-Short Municipal Income Fund | Class I  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 36
Expense Example, with Redemption, 3 Years 130
Expense Example, with Redemption, 5 Years 233
Expense Example, with Redemption, 10 Years 534
Eaton Vance National Limited Maturity Municipal Income Fund | Eaton Vance National Limited Maturity Municipal Income Fund | Class A  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 393
Expense Example, with Redemption, 3 Years 539
Expense Example, with Redemption, 5 Years 697
Expense Example, with Redemption, 10 Years 1,156
Eaton Vance National Limited Maturity Municipal Income Fund | Eaton Vance National Limited Maturity Municipal Income Fund | Class C  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 248
Expense Example, with Redemption, 3 Years 459
Expense Example, with Redemption, 5 Years 792
Expense Example, with Redemption, 10 Years 1,529
Eaton Vance National Limited Maturity Municipal Income Fund | Eaton Vance National Limited Maturity Municipal Income Fund | Class I  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 55
Expense Example, with Redemption, 3 Years 173
Expense Example, with Redemption, 5 Years 302
Expense Example, with Redemption, 10 Years 677
Eaton Vance Short Duration Municipal Opportunities Fund | Eaton Vance Short Duration Municipal Opportunities Fund | Class A  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 390
Expense Example, with Redemption, 3 Years 529
Expense Example, with Redemption, 5 Years 681
Expense Example, with Redemption, 10 Years 1,121
Eaton Vance Short Duration Municipal Opportunities Fund | Eaton Vance Short Duration Municipal Opportunities Fund | Class C  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 244
Expense Example, with Redemption, 3 Years 446
Expense Example, with Redemption, 5 Years 771
Expense Example, with Redemption, 10 Years 1,486
Eaton Vance Short Duration Municipal Opportunities Fund | Eaton Vance Short Duration Municipal Opportunities Fund | Class I  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 52
Expense Example, with Redemption, 3 Years 164
Expense Example, with Redemption, 5 Years 285
Expense Example, with Redemption, 10 Years $ 640