v3.26.1
Fees and Expenses - LOOMIS SAYLES FUNDS II
Dec. 31, 2025
USD ($)
Loomis Sayles High Income Fund  
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 73 of the Prospectus, in Appendix A to the Prospectus and on page 106 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
Shareholder Fees Caption [Optional Text] Shareholder Fees(fees paid directly from your investment)
Shareholder Fees [Table]
(fees paid directly from your investment)
Class A
Class C
Class N
Class Y
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)
4.25%
None
None
None
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)
None*
1.00%
None
None
Redemption fees
None
None
None
None
[1]
Operating Expenses Caption [Optional Text] Annual Fund Operating Expenses(expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses [Table]
(expenses that you pay each year as a percentage of the value of your investment)
Class A
Class C
Class N
Class Y
Management fees
0.55%
0.55%
0.55%
0.55%
Distribution and/or service (12b-1) fees
0.25%
1.00%
0.00%
0.00%
Other expenses
0.53%
0.53%
0.47%
0.53%
Total annual fund operating expenses
1.33%
2.08%
1.02%
1.08%
Fee waiver and/or expense reimbursement1,2
0.38%
0.38%
0.37%
0.38%
Total annual fund operating expenses after fee waiver and/or expense reimbursement
0.95%
1.70%
0.65%
0.70%
[2],[3]
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 dates 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, With Redemption [Table]
If shares are redeemed:
1 year
3 years
5 years
10 years
Class A
$
518
$
793
$
1,088
$
1,927
Class C
$
273
$
615
$
1,084
$
2,188
If shares are redeemed:
1 year
3 years
5 years
10 years
Class N
$
66
$
288
$
527
$
1,214
Class Y
$
72
$
306
$
559
$
1,283
Expense Example, No Redemption, By Year, Caption [Text] If shares are not redeemed:
Expense Example, No Redemption [Table]
If shares are not redeemed:
1 year
3 years
5 years
10 years
Class C
$
173
$
615
$
1,084
$
2,188
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 107% of the average value of its portfolio.
Portfolio Turnover, Rate 107.00%
Loomis Sayles International Growth Fund  
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 $50,000 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 73 of the Prospectus, in Appendix A to the Prospectus, and on page 106 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 $50,000 in the Natixis Funds Complex.
Expense Breakpoint, Minimum Investment Required [Amount] $ 50,000
Shareholder Fees Caption [Optional Text] Shareholder Fees(fees paid directly from your investment)
Shareholder Fees [Table]
(fees paid directly from your investment)
Class A
Class C
Class N
Class Y
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)
5.75%
None
None
None
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)
None*
1.00%
None
None
Redemption fees
None
None
None
None
[4]
Operating Expenses Caption [Optional Text] Annual Fund Operating Expenses(expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses [Table]
(expenses that you pay each year as a percentage of the value of your investment)
Class A
Class C
Class N
Class Y
Management fees
0.75%
0.75%
0.75%
0.75%
Distribution and/or service (12b-1) fees
0.25%
1.00%
0.00%
0.00%
Other expenses
0.91%1
0.88%1
0.81%
0.91%1
Total annual fund operating expenses
1.91%
2.63%
1.56%
1.66%
Fee waiver and/or expense reimbursement2,3
0.71%
0.68%
0.66%
0.71%
Total annual fund operating expenses after fee waiver and/or expense reimbursement
1.20%
1.95%
0.90%
0.95%
[5],[6],[7]
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 dates 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, With Redemption [Table]
If shares are redeemed:
1 year
3 years
5 years
10 years
Class A
$
690
$
1,076
$
1,485
$
2,625
If shares are redeemed:
1 year
3 years
5 years
10 years
Class C
$
298
$
753
$
1,334
$
2,738
Class N
$
92
$
428
$
787
$
1,800
Class Y
$
97
$
454
$
835
$
1,906
Expense Example, No Redemption, By Year, Caption [Text] If shares are not redeemed:
Expense Example, No Redemption [Table]
If shares are not redeemed:
1 year
3 years
5 years
10 years
Class C
$
198
$
753
$
1,334
$
2,738
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 9% of the average value of its portfolio.
Portfolio Turnover, Rate 9.00%
Loomis Sayles Investment Grade Bond Fund  
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 73 of the Prospectus, in Appendix A to the Prospectus and on page 106 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
Shareholder Fees Caption [Optional Text] Shareholder Fees(fees paid directly from your investment)
Shareholder Fees [Table]
(fees paid directly from your investment)
Class A
Class C
Class N
Class Y
Admin Class
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)
4.25%
None
None
None
None
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)
None*
1.00%
None
None
None
Redemption fees
None
None
None
None
None
[8]
Operating Expenses Caption [Optional Text] Annual Fund Operating Expenses(expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses [Table]
(expenses that you pay each year as a percentage of the value of your investment)
Class A
Class C
Class N
Class Y
Admin Class
Management fees1
0.38%
0.38%
0.38%
0.38%
0.38%
Distribution and/or service (12b-1) fees
0.25%
1.00%
0.00%
0.00%
0.25%
Other expenses
0.15%
0.15%
0.07%
0.15%
0.40%2
Total annual fund operating expenses
0.78%
1.53%
0.45%
0.53%
1.03%
Fee waiver and/or expense reimbursement3
0.05%
0.05%
0.02%
0.05%
0.05%
Total annual fund operating expenses after fee waiver and/or expense reimbursement
0.73%
1.48%
0.43%
0.48%
0.98%
[9],[10],[11]
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 dates 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, With Redemption [Table]
If shares are redeemed:
1 year
3 years
5 years
10 years
Class A
$
496
$
659
$
835
$
1,346
Class C
$
251
$
478
$
829
$
1,617
If shares are redeemed:
1 year
3 years
5 years
10 years
Class N
$
44
$
142
$
250
$
565
Class Y
$
49
$
165
$
291
$
660
Admin Class
$
100
$
323
$
564
$
1,255
Expense Example, No Redemption, By Year, Caption [Text] If shares are not redeemed:
Expense Example, No Redemption [Table]
If shares are not redeemed:
1 year
3 years
5 years
10 years
Class C
$
151
$
478
$
829
$
1,617
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 51% of the average value of its portfolio.
Portfolio Turnover, Rate 51.00%
Loomis Sayles Strategic Income Fund  
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 73 of the Prospectus, in Appendix A to the Prospectus and on page 106 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
Shareholder Fees Caption [Optional Text] Shareholder Fees(fees paid directly from your investment)
Shareholder Fees [Table]
(fees paid directly from your investment)
Class A
Class C
Class N
Class Y
Admin Class
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)
4.25%
None
None
None
None
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)
None*
1.00%
None
None
None
Redemption fees
None
None
None
None
None
[12]
Operating Expenses Caption [Optional Text] Annual Fund Operating Expenses(expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses [Table]
(expenses that you pay each year as a percentage of the value of your investment)
Class A
Class C
Class N
Class Y
Admin Class
Management fees
0.58%
0.58%
0.58%
0.58%
0.58%
Distribution and/or service (12b-1) fees
0.25%
1.00%
0.00%
0.00%
0.25%
Other expenses
0.17%
0.17%
0.08%
0.17%
0.42%1
Total annual fund operating expenses
1.00%
1.75%
0.66%
0.75%
1.25%
Fee waiver and/or expense reimbursement2
0.08%
0.08%
0.04%
0.08%
0.08%
Total annual fund operating expenses after fee waiver and/or expense reimbursement
0.92%
1.67%
0.62%
0.67%
1.17%
[13],[14]
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 dates 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, With Redemption [Table]
If shares are redeemed:
1 year
3 years
5 years
10 years
Class A
$
515
$
722
$
947
$
1,591
Class C
$
270
$
543
$
941
$
1,858
Class N
$
63
$
207
$
364
$
819
If shares are redeemed:
1 year
3 years
5 years
10 years
Class Y
$
68
$
232
$
409
$
923
Admin Class
$
119
$
389
$
679
$
1,504
Expense Example, No Redemption, By Year, Caption [Text] If shares are not redeemed:
Expense Example, No Redemption [Table]
If shares are not redeemed:
1 year
3 years
5 years
10 years
Class C
$
170
$
543
$
941
$
1,858
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 100% of the average value of its portfolio.
Portfolio Turnover, Rate 100.00%
[1]
*  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.
[2]
1 Loomis, Sayles & Company, L.P. (“Loomis Sayles” or the “Adviser”) has given a binding contractual undertaking to the Fund to limit the amount of the Fund’s total annual fund operating expenses to 0.95%, 1.70%, 0.65% and 0.70% of the Fund’s average daily net assets for Class A, C, N and Y shares, respectively, exclusive of brokerage expenses, interest expense, taxes, acquired fund fees and expenses, organizational and extraordinary expenses, such as litigation and indemnification expenses. This undertaking is in effect through April 30, 2027 and may be terminated before then only with the consent of the Fund’s Board of Trustees. The Adviser will be permitted to recover, on a class by class basis, management fees waived and/or expenses reimbursed to the extent that expenses in later periods fall below both (1) the class’ applicable expense limitation at the time such amounts were waived/reimbursed and (2) the class’ current applicable expense limitation. The Fund will not be obligated to repay any such waived/reimbursed fees and expenses more than one year after the end of the fiscal year in which the fees or expenses were waived/reimbursed. 
[3]
2 Natixis Advisors, LLC (“Natixis Advisors”) has given a binding contractual undertaking to the Fund to reimburse any and all transfer agency expenses for Class N shares. This undertaking is in effect through April 30, 2027 and may be terminated before then only with the consent of the Fund’s Board of Trustees.
[4]
* 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.
[5]
1 Pursuant to an expense offset arrangement, credits realized as a result of uninvested cash balances may be used to reduce the Fund’s transfer agent expenses. Other expenses are shown net of such reductions of transfer agent expenses of 1bps.
[6]
2 Loomis, Sayles & Company, L.P. (“Loomis Sayles” or the “Adviser”) has given a binding contractual undertaking to the Fund to limit the amount of the Fund’s total annual fund operating expenses to 1.20%, 1.95%, 0.90% and 0.95% of the Fund’s average daily net assets for Class A, C, N and Y shares, respectively, exclusive of brokerage expenses, interest expense, taxes, acquired fund fees and expenses, organizational and extraordinary expenses, such as litigation and indemnification expenses. This undertaking is in effect through April 30, 2027 and may be terminated before then only with the consent of the Fund’s Board of Trustees. The Adviser will be permitted to recover, on a class by class basis, management fees waived and/or expenses reimbursed to the extent that expenses in later periods fall below both (1) the class’ applicable expense limitation at the time such amounts were waived/reimbursed and (2) the class’ current applicable expense limitation. The Fund will not be obligated to repay any such waived/reimbursed fees and expenses more than one year after the end of the fiscal year in which the fees or expenses were waived/reimbursed.
[7]
3 Natixis Advisors, LLC (“Natixis Advisors”) has given a binding contractual undertaking to the Fund to reimburse any and all transfer agency expenses for Class N shares. This undertaking is in effect through April 30, 2027 and may be terminated before then only with the consent of the Fund’s Board of Trustees.
[8]
* 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.
[9]
1 The Fund’s operating expenses have been restated to reflect a reduction in management fees, effective as of January 1, 2026, as if reduction had been in effect during the fiscal year ended December 31, 2025. The information has been restated to better reflect anticipated expenses of the Fund.
[10]
2 Other expenses include an administrative services fee of 0.25% for Admin Class shares.
[11]
3 Loomis, Sayles & Company, L.P. (“Loomis Sayles” or the “Adviser”) has given a binding contractual undertaking to the Fund to limit the amount of the Fund’s total annual fund operating expenses to 0.73%, 1.48%, 0.43%, 0.48% and 0.98% of the Fund’s average daily net assets for Class A, Class C, Class N, Class Y and Admin Class shares, respectively, exclusive of brokerage expenses, interest expense, taxes, acquired fund fees and expenses, organizational and extraordinary expenses, such as litigation and indemnification expenses. This undertaking is in effect through April 30, 2027 and may be terminated before then only with the consent of the Fund’s Board of Trustees. The Adviser will be permitted to recover, on a class by class basis, management fees waived and/or expenses reimbursed to the extent that expenses in later periods fall below both (1) the class’ applicable expense limitation at the time such amounts were waived/reimbursed and (2) the class’ current applicable expense limitation. The Fund will not be obligated to repay any such waived/reimbursed fees and expenses more than one year after the end of the fiscal year in which the fees or expenses were waived/reimbursed.
[12]
* 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.
[13]
1 Other expenses include an administrative services fee of 0.25% for Admin Class shares.
[14]
2 Loomis, Sayles & Company, L.P. (“Loomis Sayles” or the “Adviser”) has given a binding contractual undertaking to the Fund to limit the amount of the Fund’s total annual fund operating expenses to 0.92%, 1.67%, 0.62%, 0.67% and 1.17% of the Fund’s average daily net assets for Class A, C, N, Y and Admin Class shares, respectively, exclusive of brokerage expenses, interest expense, taxes, acquired fund fees and expenses, organizational and extraordinary expenses, such as litigation and indemnification expenses. This undertaking is in effect through April 30, 2027 and may be terminated before then only with the consent of the Fund’s Board of Trustees. The Adviser will be permitted to recover, on a class by class basis, management fees waived and/or expenses reimbursed to the extent that expenses in later periods fall below both (1) the class’ applicable expense limitation at the time such amounts were waived/reimbursed and (2) the class’ current applicable expense limitation. The Fund will not be obligated to repay any such waived/reimbursed fees and expenses more than one year after the end of the fiscal year in which the fees or expenses were waived/reimbursed.