This semi-annual shareholder report contains important information about Gateway Equity Call Premium Fund for the period of January 1, 2026 to June 30, 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

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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 investment^{Footnote Reference†}
Class A	$48	0.93%

Footnote	Description
Footnote^†	Annualized for periods less than one year (if applicable).

Expenses Paid, Amount

$ 48

Expense Ratio, Percent

0.93%

AssetsNet

$ 333,770,090

Holdings Count | Holding

291

Advisory Fees Paid, Amount

$ 725,975

InvestmentCompanyPortfolioTurnover

15.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$333,770,090
# of Portfolio Holdings (including overnight repurchase agreements and derivatives)291
Portfolio Turnover Rate15%
Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$725,975

Holdings [Text Block]

Industry Summary

Table Summary
Value	Value
Other investments less than 3% of net assets^{Footnote Reference*}	42.8%
Banks	3.5%
Pharmaceuticals	3.7%
Broadline Retail	3.8%
Financial Services	3.9%
Software	7.5%
Interactive Media & Services	7.8%
Technology Hardware, Storage & Peripherals	8.0%
Semiconductors & Semiconductor Equipment	19.0%

Footnote	Description
Footnote^*	Net of other assets less liabilities (including open written options)

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
NVIDIA Corp.	7.5%
Apple, Inc.	6.7%
Microsoft Corp.	4.3%
Amazon.com, Inc.	3.8%
Alphabet, Inc., Class C	3.2%
Broadcom, Inc.	2.8%
Alphabet, Inc., Class A	2.6%
Micron Technology, Inc.	2.1%
Meta Platforms, Inc., Class A	2.0%
Tesla, Inc.	2.0%

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.

C000146364

Shareholder Report [Line Items]

Fund Name

Gateway Equity Call Premium Fund

Class Name

Class C

Trading Symbol

GCPCX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about Gateway Equity Call Premium Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

(800) 225-5478

Additional Information Website

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 investment^{Footnote Reference†}
Class C	$86	1.68%

Footnote	Description
Footnote^†	Annualized for periods less than one year (if applicable).

Expenses Paid, Amount

$ 86

Expense Ratio, Percent

1.68%

AssetsNet

$ 333,770,090

Holdings Count | Holding

291

Advisory Fees Paid, Amount

$ 725,975

InvestmentCompanyPortfolioTurnover

15.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$333,770,090
# of Portfolio Holdings (including overnight repurchase agreements and derivatives)291
Portfolio Turnover Rate15%
Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$725,975

Holdings [Text Block]

Industry Summary

Table Summary
Value	Value
Other investments less than 3% of net assets^{Footnote Reference*}	42.8%
Banks	3.5%
Pharmaceuticals	3.7%
Broadline Retail	3.8%
Financial Services	3.9%
Software	7.5%
Interactive Media & Services	7.8%
Technology Hardware, Storage & Peripherals	8.0%
Semiconductors & Semiconductor Equipment	19.0%

Footnote	Description
Footnote^*	Net of other assets less liabilities (including open written options)

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
NVIDIA Corp.	7.5%
Apple, Inc.	6.7%
Microsoft Corp.	4.3%
Amazon.com, Inc.	3.8%
Alphabet, Inc., Class C	3.2%
Broadcom, Inc.	2.8%
Alphabet, Inc., Class A	2.6%
Micron Technology, Inc.	2.1%
Meta Platforms, Inc., Class A	2.0%
Tesla, Inc.	2.0%

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.

C000190731

Shareholder Report [Line Items]

Fund Name

Gateway Equity Call Premium Fund

Class Name

Class N

Trading Symbol

GCPNX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about Gateway Equity Call Premium Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

(800) 225-5478

Additional Information Website

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 investment^{Footnote Reference†}
Class N	$32	0.63%

Footnote	Description
Footnote^†	Annualized for periods less than one year (if applicable).

Expenses Paid, Amount

$ 32

Expense Ratio, Percent

0.63%

AssetsNet

$ 333,770,090

Holdings Count | Holding

291

Advisory Fees Paid, Amount

$ 725,975

InvestmentCompanyPortfolioTurnover

15.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$333,770,090
# of Portfolio Holdings (including overnight repurchase agreements and derivatives)291
Portfolio Turnover Rate15%
Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$725,975

Holdings [Text Block]

Industry Summary

Table Summary
Value	Value
Other investments less than 3% of net assets^{Footnote Reference*}	42.8%
Banks	3.5%
Pharmaceuticals	3.7%
Broadline Retail	3.8%
Financial Services	3.9%
Software	7.5%
Interactive Media & Services	7.8%
Technology Hardware, Storage & Peripherals	8.0%
Semiconductors & Semiconductor Equipment	19.0%

Footnote	Description
Footnote^*	Net of other assets less liabilities (including open written options)

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
NVIDIA Corp.	7.5%
Apple, Inc.	6.7%
Microsoft Corp.	4.3%
Amazon.com, Inc.	3.8%
Alphabet, Inc., Class C	3.2%
Broadcom, Inc.	2.8%
Alphabet, Inc., Class A	2.6%
Micron Technology, Inc.	2.1%
Meta Platforms, Inc., Class A	2.0%
Tesla, Inc.	2.0%

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.

C000146365

Shareholder Report [Line Items]

Fund Name

Gateway Equity Call Premium Fund

Class Name

Class Y

Trading Symbol

GCPYX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about Gateway Equity Call Premium Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

(800) 225-5478

Additional Information Website

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 investment^{Footnote Reference†}
Class Y	$35	0.68%

Footnote	Description
Footnote^†	Annualized for periods less than one year (if applicable).

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.68%

AssetsNet

$ 333,770,090

Holdings Count | Holding

291

Advisory Fees Paid, Amount

$ 725,975

InvestmentCompanyPortfolioTurnover

15.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$333,770,090
# of Portfolio Holdings (including overnight repurchase agreements and derivatives)291
Portfolio Turnover Rate15%
Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$725,975

Holdings [Text Block]

Industry Summary

Table Summary
Value	Value
Other investments less than 3% of net assets^{Footnote Reference*}	42.8%
Banks	3.5%
Pharmaceuticals	3.7%
Broadline Retail	3.8%
Financial Services	3.9%
Software	7.5%
Interactive Media & Services	7.8%
Technology Hardware, Storage & Peripherals	8.0%
Semiconductors & Semiconductor Equipment	19.0%

Footnote	Description
Footnote^*	Net of other assets less liabilities (including open written options)

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
NVIDIA Corp.	7.5%
Apple, Inc.	6.7%
Microsoft Corp.	4.3%
Amazon.com, Inc.	3.8%
Alphabet, Inc., Class C	3.2%
Broadcom, Inc.	2.8%
Alphabet, Inc., Class A	2.6%
Micron Technology, Inc.	2.1%
Meta Platforms, Inc., Class A	2.0%
Tesla, Inc.	2.0%

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.

C000052969

Shareholder Report [Line Items]

Fund Name

Gateway Fund

Class Name

Class A

Trading Symbol

GATEX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about Gateway Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

(800) 225-5478

Additional Information Website

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 investment^{Footnote Reference†}
Class A	$47	0.93%

Footnote	Description
Footnote^†	Annualized for periods less than one year (if applicable).

Expenses Paid, Amount

$ 47

Expense Ratio, Percent

0.93%

AssetsNet

$ 7,297,251,526

Holdings Count | Holding

226

Advisory Fees Paid, Amount

$ 20,131,908

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$7,297,251,526
# of Portfolio Holdings (including overnight repurchase agreements and derivatives)226
Portfolio Turnover Rate5%
Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$20,131,908

Holdings [Text Block]

Industry Summary

Table Summary
Value	Value
Other investments less than 3% of net assets^{Footnote Reference*}	36.7%
Oil, Gas & Consumable Fuels	3.0%
Machinery	3.4%
Pharmaceuticals	3.6%
Financial Services	3.7%
Banks	3.8%
Broadline Retail	4.0%
Software	7.1%
Interactive Media & Services	8.1%
Technology Hardware, Storage & Peripherals	8.4%
Semiconductors & Semiconductor Equipment	18.2%

Footnote	Description
Footnote^*	Net of other assets less liabilities (including open purchased and written options)

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
NVIDIA Corp.	7.7%
Apple, Inc.	6.8%
Microsoft Corp.	4.7%
Alphabet, Inc., Class C	4.6%
Amazon.com, Inc.	4.0%
Broadcom, Inc.	2.9%
JPMorgan Chase & Co.	2.2%
Meta Platforms, Inc., Class A	2.1%
Micron Technology, Inc.	2.1%
Tesla, Inc.	1.9%

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.

C000052970

Shareholder Report [Line Items]

Fund Name

Gateway Fund

Class Name

Class C

Trading Symbol

GTECX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about Gateway Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

(800) 225-5478

Additional Information Website

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 investment^{Footnote Reference†}
Class C	$86	1.70%

Footnote	Description
Footnote^†	Annualized for periods less than one year (if applicable).

Expenses Paid, Amount

$ 86

Expense Ratio, Percent

1.70%

AssetsNet

$ 7,297,251,526

Holdings Count | Holding

226

Advisory Fees Paid, Amount

$ 20,131,908

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$7,297,251,526
# of Portfolio Holdings (including overnight repurchase agreements and derivatives)226
Portfolio Turnover Rate5%
Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$20,131,908

Holdings [Text Block]

Industry Summary

Table Summary
Value	Value
Other investments less than 3% of net assets^{Footnote Reference*}	36.7%
Oil, Gas & Consumable Fuels	3.0%
Machinery	3.4%
Pharmaceuticals	3.6%
Financial Services	3.7%
Banks	3.8%
Broadline Retail	4.0%
Software	7.1%
Interactive Media & Services	8.1%
Technology Hardware, Storage & Peripherals	8.4%
Semiconductors & Semiconductor Equipment	18.2%

Footnote	Description
Footnote^*	Net of other assets less liabilities (including open purchased and written options)

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
NVIDIA Corp.	7.7%
Apple, Inc.	6.8%
Microsoft Corp.	4.7%
Alphabet, Inc., Class C	4.6%
Amazon.com, Inc.	4.0%
Broadcom, Inc.	2.9%
JPMorgan Chase & Co.	2.2%
Meta Platforms, Inc., Class A	2.1%
Micron Technology, Inc.	2.1%
Tesla, Inc.	1.9%

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.

C000190730

Shareholder Report [Line Items]

Fund Name

Gateway Fund

Class Name

Class N

Trading Symbol

GTENX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about Gateway Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

(800) 225-5478

Additional Information Website

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 investment^{Footnote Reference†}
Class N	$33	0.65%

Footnote	Description
Footnote^†	Annualized for periods less than one year (if applicable).

Expenses Paid, Amount

$ 33

Expense Ratio, Percent

0.65%

AssetsNet

$ 7,297,251,526

Holdings Count | Holding

226

Advisory Fees Paid, Amount

$ 20,131,908

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$7,297,251,526
# of Portfolio Holdings (including overnight repurchase agreements and derivatives)226
Portfolio Turnover Rate5%
Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$20,131,908

Holdings [Text Block]

Industry Summary

Table Summary
Value	Value
Other investments less than 3% of net assets^{Footnote Reference*}	36.7%
Oil, Gas & Consumable Fuels	3.0%
Machinery	3.4%
Pharmaceuticals	3.6%
Financial Services	3.7%
Banks	3.8%
Broadline Retail	4.0%
Software	7.1%
Interactive Media & Services	8.1%
Technology Hardware, Storage & Peripherals	8.4%
Semiconductors & Semiconductor Equipment	18.2%

Footnote	Description
Footnote^*	Net of other assets less liabilities (including open purchased and written options)

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
NVIDIA Corp.	7.7%
Apple, Inc.	6.8%
Microsoft Corp.	4.7%
Alphabet, Inc., Class C	4.6%
Amazon.com, Inc.	4.0%
Broadcom, Inc.	2.9%
JPMorgan Chase & Co.	2.2%
Meta Platforms, Inc., Class A	2.1%
Micron Technology, Inc.	2.1%
Tesla, Inc.	1.9%

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.

C000052971

Shareholder Report [Line Items]

Fund Name

Gateway Fund

Class Name

Class Y

Trading Symbol

GTEYX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about Gateway Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

(800) 225-5478

Additional Information Website

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 investment^{Footnote Reference†}
Class Y	$35	0.70%

Footnote	Description
Footnote^†	Annualized for periods less than one year (if applicable).

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.70%

AssetsNet

$ 7,297,251,526

Holdings Count | Holding

226

Advisory Fees Paid, Amount

$ 20,131,908

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$7,297,251,526
# of Portfolio Holdings (including overnight repurchase agreements and derivatives)226
Portfolio Turnover Rate5%
Total Advisory Fees Paid (after waiver/reimbursement, if applicable)$20,131,908

Holdings [Text Block]

Industry Summary

Table Summary
Value	Value
Other investments less than 3% of net assets^{Footnote Reference*}	36.7%
Oil, Gas & Consumable Fuels	3.0%
Machinery	3.4%
Pharmaceuticals	3.6%
Financial Services	3.7%
Banks	3.8%
Broadline Retail	4.0%
Software	7.1%
Interactive Media & Services	8.1%
Technology Hardware, Storage & Peripherals	8.4%
Semiconductors & Semiconductor Equipment	18.2%

Footnote	Description
Footnote^*	Net of other assets less liabilities (including open purchased and written options)

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
NVIDIA Corp.	7.7%
Apple, Inc.	6.8%
Microsoft Corp.	4.7%
Alphabet, Inc., Class C	4.6%
Amazon.com, Inc.	4.0%
Broadcom, Inc.	2.9%
JPMorgan Chase & Co.	2.2%
Meta Platforms, Inc., Class A	2.1%
Micron Technology, Inc.	2.1%
Tesla, Inc.	1.9%

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.