v3.26.3
Shareholder Report
 6 Months Ended
Jul. 31, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name Natixis Funds Trust IV
Entity Central Index Key 0001095726
Entity Investment Company Type N-1A
Document Period End Date Jul. 31, 2026
Shareholder Report Annual or Semi-Annual Semi-annual Shareholder Report
C000021867  
Shareholder Report [Line Items]  
Fund Name AEW Global Focused Real Estate Fund
Class Name Class A
Trading Symbol NRFAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about AEW Global Focused Real Estate Fund for the period of February 1, 2026 to July 31, 2026.
Additional Information [Text Block] You can find additional information (including tax information) about the Fund at im.natixis.com/funddocuments. You can also request the information by contacting us at (800) 225-5478 or by contacting your financial intermediary directly.
Additional Information Phone Number (800) 225-5478
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; line-height: 18px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">im.natixis.com/funddocuments</span>
Expenses [Text Block]

What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investmentFootnote Reference†
Class A
$60
1.15%
Footnote Description
Footnote†
 Annualized for periods less than one year (if applicable).
Expenses Paid, Amount $ 60
Expense Ratio, Percent 1.15%
AssetsNet $ 36,255,393
Holdings Count | Holding 61
Advisory Fees Paid, Amount $ 0
InvestmentCompanyPortfolioTurnover 17.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

  • Total Net Assets$36,255,393
  • # of Portfolio Holdings (including overnight repurchase agreements)61
  • Portfolio Turnover Rate17%
  • Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$0
Holdings [Text Block]

Industry Summary

Group By Sector Chart
Table Summary
Value
Value
Other investments less than 3% of net assetsFootnote Reference*
1.2%
Office REITs
5.1%
Diversified REITs
7.8%
Residential REITs
10.0%
Real Estate Management & Development
11.2%
Health Care REITs
12.3%
Industrial REITs
13.8%
Retail REITs
18.2%
Specialized REITs
20.4%
Footnote Description
Footnote*
 Net of other assets less liabilities

Country Weightings

Group By Country Chart
Table Summary
Value
Value
Other investments less than 3% of net assetsFootnote Reference*
10.8%
Hong Kong
3.3%
United Kingdom
3.8%
Australia
6.3%
Japan
7.7%
United States
68.1%
Footnote Description
Footnote*
 Net of other assets less liabilities
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Welltower, Inc.
11.6%
Prologis, Inc.
6.4%
Equinix, Inc.
5.1%
CubeSmart
4.0%
Simon Property Group, Inc.
4.0%
Digital Realty Trust, Inc.
3.9%
AvalonBay Communities, Inc.
3.7%
Highwoods Properties, Inc.
3.4%
Essex Property Trust, Inc.
3.3%
Brixmor Property Group, Inc.
3.1%
Material Fund Change [Text Block]

Material Fund Changes 

There were no material fund changes during the period. 
Summary of Change Legend [Text Block]

There were no material fund changes during the period. 
C000021869  
Shareholder Report [Line Items]  
Fund Name AEW Global Focused Real Estate Fund
Class Name Class C
Trading Symbol NRCFX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about AEW Global Focused Real Estate Fund for the period of February 1, 2026 to July 31, 2026.
Additional Information [Text Block] You can find additional information (including tax information) about the Fund at im.natixis.com/funddocuments. You can also request the information by contacting us at (800) 225-5478 or by contacting your financial intermediary directly.
Additional Information Phone Number (800) 225-5478
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; line-height: 18px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">im.natixis.com/funddocuments</span>
Expenses [Text Block]

What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investmentFootnote Reference†
Class C
$99
1.90%
Footnote Description
Footnote†
 Annualized for periods less than one year (if applicable).
Expenses Paid, Amount $ 99
Expense Ratio, Percent 1.90%
AssetsNet $ 36,255,393
Holdings Count | Holding 61
Advisory Fees Paid, Amount $ 0
InvestmentCompanyPortfolioTurnover 17.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

  • Total Net Assets$36,255,393
  • # of Portfolio Holdings (including overnight repurchase agreements)61
  • Portfolio Turnover Rate17%
  • Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$0
Holdings [Text Block]

Industry Summary

Group By Sector Chart
Table Summary
Value
Value
Other investments less than 3% of net assetsFootnote Reference*
1.2%
Office REITs
5.1%
Diversified REITs
7.8%
Residential REITs
10.0%
Real Estate Management & Development
11.2%
Health Care REITs
12.3%
Industrial REITs
13.8%
Retail REITs
18.2%
Specialized REITs
20.4%
Footnote Description
Footnote*
 Net of other assets less liabilities

Country Weightings

Group By Country Chart
Table Summary
Value
Value
Other investments less than 3% of net assetsFootnote Reference*
10.8%
Hong Kong
3.3%
United Kingdom
3.8%
Australia
6.3%
Japan
7.7%
United States
68.1%
Footnote Description
Footnote*
 Net of other assets less liabilities
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Welltower, Inc.
11.6%
Prologis, Inc.
6.4%
Equinix, Inc.
5.1%
CubeSmart
4.0%
Simon Property Group, Inc.
4.0%
Digital Realty Trust, Inc.
3.9%
AvalonBay Communities, Inc.
3.7%
Highwoods Properties, Inc.
3.4%
Essex Property Trust, Inc.
3.3%
Brixmor Property Group, Inc.
3.1%
Material Fund Change [Text Block]

Material Fund Changes 

There were no material fund changes during the period. 
Summary of Change Legend [Text Block]

There were no material fund changes during the period. 
C000128774  
Shareholder Report [Line Items]  
Fund Name AEW Global Focused Real Estate Fund
Class Name Class N
Trading Symbol NRFNX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about AEW Global Focused Real Estate Fund for the period of February 1, 2026 to July 31, 2026.
Additional Information [Text Block] You can find additional information (including tax information) about the Fund at im.natixis.com/funddocuments. You can also request the information by contacting us at (800) 225-5478 or by contacting your financial intermediary directly.
Additional Information Phone Number (800) 225-5478
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; line-height: 18px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">im.natixis.com/funddocuments</span>
Expenses [Text Block]

What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investmentFootnote Reference†
Class N
$44
0.85%
Footnote Description
Footnote†
 Annualized for periods less than one year (if applicable).
Expenses Paid, Amount $ 44
Expense Ratio, Percent 0.85%
AssetsNet $ 36,255,393
Holdings Count | Holding 61
Advisory Fees Paid, Amount $ 0
InvestmentCompanyPortfolioTurnover 17.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

  • Total Net Assets$36,255,393
  • # of Portfolio Holdings (including overnight repurchase agreements)61
  • Portfolio Turnover Rate17%
  • Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$0
Holdings [Text Block]

Industry Summary

Group By Sector Chart
Table Summary
Value
Value
Other investments less than 3% of net assetsFootnote Reference*
1.2%
Office REITs
5.1%
Diversified REITs
7.8%
Residential REITs
10.0%
Real Estate Management & Development
11.2%
Health Care REITs
12.3%
Industrial REITs
13.8%
Retail REITs
18.2%
Specialized REITs
20.4%
Footnote Description
Footnote*
 Net of other assets less liabilities

Country Weightings

Group By Country Chart
Table Summary
Value
Value
Other investments less than 3% of net assetsFootnote Reference*
10.8%
Hong Kong
3.3%
United Kingdom
3.8%
Australia
6.3%
Japan
7.7%
United States
68.1%
Footnote Description
Footnote*
 Net of other assets less liabilities
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Welltower, Inc.
11.6%
Prologis, Inc.
6.4%
Equinix, Inc.
5.1%
CubeSmart
4.0%
Simon Property Group, Inc.
4.0%
Digital Realty Trust, Inc.
3.9%
AvalonBay Communities, Inc.
3.7%
Highwoods Properties, Inc.
3.4%
Essex Property Trust, Inc.
3.3%
Brixmor Property Group, Inc.
3.1%
Material Fund Change [Text Block]

Material Fund Changes 

There were no material fund changes during the period. 
Summary of Change Legend [Text Block]

There were no material fund changes during the period. 
C000021870  
Shareholder Report [Line Items]  
Fund Name AEW Global Focused Real Estate Fund
Class Name Class Y
Trading Symbol NRFYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about AEW Global Focused Real Estate Fund for the period of February 1, 2026 to July 31, 2026.
Additional Information [Text Block] You can find additional information (including tax information) about the Fund at im.natixis.com/funddocuments. You can also request the information by contacting us at (800) 225-5478 or by contacting your financial intermediary directly.
Additional Information Phone Number (800) 225-5478
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; line-height: 18px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">im.natixis.com/funddocuments</span>
Expenses [Text Block]

What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investmentFootnote Reference†
Class Y
$47
0.90%
Footnote Description
Footnote†
 Annualized for periods less than one year (if applicable).
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.90%
AssetsNet $ 36,255,393
Holdings Count | Holding 61
Advisory Fees Paid, Amount $ 0
InvestmentCompanyPortfolioTurnover 17.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

  • Total Net Assets$36,255,393
  • # of Portfolio Holdings (including overnight repurchase agreements)61
  • Portfolio Turnover Rate17%
  • Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$0
Holdings [Text Block]

Industry Summary

Group By Sector Chart
Table Summary
Value
Value
Other investments less than 3% of net assetsFootnote Reference*
1.2%
Office REITs
5.1%
Diversified REITs
7.8%
Residential REITs
10.0%
Real Estate Management & Development
11.2%
Health Care REITs
12.3%
Industrial REITs
13.8%
Retail REITs
18.2%
Specialized REITs
20.4%
Footnote Description
Footnote*
 Net of other assets less liabilities

Country Weightings

Group By Country Chart
Table Summary
Value
Value
Other investments less than 3% of net assetsFootnote Reference*
10.8%
Hong Kong
3.3%
United Kingdom
3.8%
Australia
6.3%
Japan
7.7%
United States
68.1%
Footnote Description
Footnote*
 Net of other assets less liabilities
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Welltower, Inc.
11.6%
Prologis, Inc.
6.4%
Equinix, Inc.
5.1%
CubeSmart
4.0%
Simon Property Group, Inc.
4.0%
Digital Realty Trust, Inc.
3.9%
AvalonBay Communities, Inc.
3.7%
Highwoods Properties, Inc.
3.4%
Essex Property Trust, Inc.
3.3%
Brixmor Property Group, Inc.
3.1%
Material Fund Change [Text Block]

Material Fund Changes 

There were no material fund changes during the period. 
Summary of Change Legend [Text Block]

There were no material fund changes during the period.