S000034097 [Member] Fees and Expenses - Loomis Sayles Senior Floating Rate and Fixed Income Fund	Nov. 30, 2025 USD ($)
Prospectus [Line Items]
Expense Heading [Optional Text]	Fund Fees & Expenses
Expense Narrative [Text Block]	The following table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in this table. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in the Natixis Funds Complex. More information about these and other discounts is available from your financial professional and in the section “How Sales Charges Are Calculated” on page 34 of the Prospectus, in Appendix A to the Prospectus and on page 85 in the section “Reduced Sales Charges” of the Statement of Additional Information (“SAI”).
Expense Breakpoint Discounts [Text]	You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in the Natixis Funds Complex.
Expense Breakpoint, Minimum Investment Required [Amount]	$ 100,000
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	The expense information shown in the table above includes acquired fund fees and expenses of less than 0.01%; the ratios may differ from the expense information disclosed in the Fund’s financial highlights table because the financial highlights table reflects the operating expenses of the Fund and does not include acquired fund fees and expenses.
Shareholder Fees Caption [Optional Text]	Shareholder Fees(fees paid directly from your investment)
Operating Expenses Caption [Optional Text]	Annual Fund Operating Expenses(expenses that you pay each year as a percentage of the value of your investment)
Expenses Deferred Charges [Text Block]	A 1.00% contingent deferred sales charge (“CDSC”) may apply to certain purchases of Class A shares of $1,000,000 or more that are redeemed within eighteen months of the date of purchase.
Expense Example [Heading]	Example
Expense Example Narrative [Text Block]	This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods (except where indicated). The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same, except that the example is based on the Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement assuming that such waiver and/or reimbursement will only be in place through the date noted above and on the Total Annual Fund Operating Expenses for the remaining periods. The example for Class C shares for the ten-year period reflects the conversion to Class A shares after eight years. The example does not take into account brokerage commissions and other fees to financial intermediaries that you may pay on your purchases and sales of shares of the Fund. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example by, Year, Caption [Text]	If shares are redeemed:
Expense Example, No Redemption, By Year, Caption [Text]	If shares are not redeemed:
Portfolio Turnover [Heading]	Portfolio Turnover
Portfolio Turnover [Text Block]	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes for you if your Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During its most recently ended fiscal year, the Fund’s portfolio turnover rate was 127% of the average value of its portfolio.
Portfolio Turnover, Rate	127.00%

S000034097 [Member] Fees and Expenses - Loomis Sayles Senior Floating Rate and Fixed Income Fund

Nov. 30, 2025

USD ($)

Fund Fees & Expenses

The following table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in this table. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in the Natixis Funds Complex. More information about these and other discounts is available from your financial professional and in the section “How Sales Charges Are Calculated” on page 34 of the Prospectus, in Appendix A to the Prospectus and on page 85 in the section “Reduced Sales Charges” of the Statement of Additional Information (“SAI”).

Expense Breakpoint Discounts [Text]

You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in the Natixis Funds Complex.

Expense Breakpoint, Minimum Investment Required [Amount]

$ 100,000

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

The expense information shown in the table above includes acquired fund fees and expenses of less than 0.01%; the ratios may differ from the expense information disclosed in the Fund’s financial highlights table because the financial highlights table reflects the operating expenses of the Fund and does not include acquired fund fees and expenses.

Shareholder Fees Caption [Optional Text]

Shareholder Fees(fees paid directly from your investment)

Operating Expenses Caption [Optional Text]

Annual Fund Operating Expenses(expenses that you pay each year as a percentage of the value of your investment)

Expenses Deferred Charges [Text Block]

A 1.00% contingent deferred sales charge (“CDSC”) may apply to certain purchases of Class A shares of $1,000,000 or more that are redeemed within eighteen months of the date of purchase.

Expense Example [Heading]

Example

Expense Example Narrative [Text Block]

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods (except where indicated). The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same, except that the example is based on the Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement assuming that such waiver and/or reimbursement will only be in place through the date noted above and on the Total Annual Fund Operating Expenses for the remaining periods. The example for Class C shares for the ten-year period reflects the conversion to Class A shares after eight years. The example does not take into account brokerage commissions and other fees

to financial intermediaries that you may pay on your purchases and sales of shares of the Fund. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example by, Year, Caption [Text]

If shares are redeemed:

Expense Example, No Redemption, By Year, Caption [Text]

If shares are not redeemed:

Portfolio Turnover [Heading]

Portfolio Turnover

Portfolio Turnover [Text Block]

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes for you if your Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During its most recently ended fiscal year, the Fund’s portfolio turnover rate was 127% of the average value of its portfolio.

Portfolio Turnover, Rate

127.00%