Annual Fund Operating Expenses - Loomis Sayles Funds I - Classes Admin, Retail, Institutional, and N |
Dec. 31, 2025 |
|||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Loomis Sayles Income Fund | ||||||||||||||||||
| Prospectus [Line Items] | ||||||||||||||||||
| Fee Waiver or Reimbursement over Assets, Date of Termination | April 30, 2027 | |||||||||||||||||
| Loomis Sayles Income Fund | Institutional | ||||||||||||||||||
| Prospectus [Line Items] | ||||||||||||||||||
| Management Fees (as a percentage of Assets) | 0.56% | |||||||||||||||||
| Distribution and Service (12b-1) Fees | 0.00% | |||||||||||||||||
| Other Expenses (as a percentage of Assets): | 0.15% | |||||||||||||||||
| Expenses (as a percentage of Assets) | 0.71% | |||||||||||||||||
| Fee Waiver or Reimbursement | 0.07% | [1] | ||||||||||||||||
| Net Expenses (as a percentage of Assets) | 0.64% | |||||||||||||||||
| Loomis Sayles Income Fund | Retail | ||||||||||||||||||
| Prospectus [Line Items] | ||||||||||||||||||
| Management Fees (as a percentage of Assets) | 0.56% | |||||||||||||||||
| Distribution and Service (12b-1) Fees | 0.25% | |||||||||||||||||
| Other Expenses (as a percentage of Assets): | 0.15% | |||||||||||||||||
| Expenses (as a percentage of Assets) | 0.96% | |||||||||||||||||
| Fee Waiver or Reimbursement | 0.07% | [1] | ||||||||||||||||
| Net Expenses (as a percentage of Assets) | 0.89% | |||||||||||||||||
| Loomis Sayles Income Fund | Admin | ||||||||||||||||||
| Prospectus [Line Items] | ||||||||||||||||||
| Management Fees (as a percentage of Assets) | 0.56% | |||||||||||||||||
| Distribution and Service (12b-1) Fees | 0.25% | |||||||||||||||||
| Other Expenses (as a percentage of Assets): | 0.39% | [2] | ||||||||||||||||
| Expenses (as a percentage of Assets) | 1.20% | |||||||||||||||||
| Fee Waiver or Reimbursement | 0.06% | [1],[3] | ||||||||||||||||
| Net Expenses (as a percentage of Assets) | 1.14% | |||||||||||||||||
| Loomis Sayles Income Fund | N | ||||||||||||||||||
| Prospectus [Line Items] | ||||||||||||||||||
| Management Fees (as a percentage of Assets) | 0.56% | |||||||||||||||||
| Distribution and Service (12b-1) Fees | 0.00% | |||||||||||||||||
| Other Expenses (as a percentage of Assets): | 0.07% | |||||||||||||||||
| Expenses (as a percentage of Assets) | 0.63% | |||||||||||||||||
| Fee Waiver or Reimbursement | 0.04% | [1] | ||||||||||||||||
| Net Expenses (as a percentage of Assets) | 0.59% | |||||||||||||||||
| Loomis Sayles Investment Grade Fixed Income Fund | ||||||||||||||||||
| Prospectus [Line Items] | ||||||||||||||||||
| Fee Waiver or Reimbursement over Assets, Date of Termination | April 30, 2027 | |||||||||||||||||
| Loomis Sayles Investment Grade Fixed Income Fund | Institutional | ||||||||||||||||||
| Prospectus [Line Items] | ||||||||||||||||||
| Management Fees (as a percentage of Assets) | 0.40% | |||||||||||||||||
| Distribution and Service (12b-1) Fees | 0.00% | |||||||||||||||||
| Other Expenses (as a percentage of Assets): | 0.19% | |||||||||||||||||
| Expenses (as a percentage of Assets) | 0.59% | |||||||||||||||||
| Fee Waiver or Reimbursement | 0.06% | [4] | ||||||||||||||||
| Net Expenses (as a percentage of Assets) | 0.53% | |||||||||||||||||
| ||||||||||||||||||