v3.26.1
Shareholder Report
 6 Months Ended
Jun. 30, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name DEUTSCHE DWS INSTITUTIONAL FUNDS
Entity Central Index Key 0000862157
Entity Investment Company Type N-1A
Document Period End Date Jun. 30, 2026
Shareholder Report Annual or Semi-Annual Semi-Annual Shareholder Report
C000188490  
Shareholder Report [Line Items]  
Fund Name DWS Equity 500 Index Fund
Class Name Class R6
Trading Symbol BTIRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about DWS Equity 500 Index Fund (the "Fund") for the period January 1, 2026 to June 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund on the Fund's website at dws.com/mutualreports. You can also request this information by contacting us at (800) 728-3337.
Additional Information Phone Number (800) 728-3337
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 14.6667px; font-weight: 300; grid-area: auto; line-height: 17.6px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">dws.com/mutualreports</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Fund
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class R6
$10
0.20%Footnote Reference(a)
FootnoteDescription
Footnote(a)
Annualized.

The Fund is a feeder fund which invests all of its investable assets in a master portfolio, Deutsche DWS Equity 500 Index Portfolio. Fund costs reflect the expenses of both the feeder and master fund.

Gross expense ratio as of the latest prospectus: 0.23%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher.

Expenses Paid, Amount $ 10
Expense Ratio, Percent 0.20% [1]
Expenses Represent Both Master and Feeder [Text] The Fund is a feeder fund which invests all of its investable assets in a master portfolio, Deutsche DWS Equity 500 Index Portfolio. Fund costs reflect the expenses of both the feeder and master fund.
AssetsNet $ 426,997,498
Holdings Count | Holding 506
Advisory Fees Paid, Amount $ 105,999
InvestmentCompanyPortfolioTurnover 1.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Net Assets ($)
426,997,498
Number of Portfolio Holdings
506
Portfolio Turnover Rate (%)
1
Total Net Advisory Fees Paid ($)
105,999
Holdings [Text Block]

Asset Allocation

Table Summary
Asset Type
% of Net Assets
Common Stocks
98%
Cash Equivalents
1%
Government & Agency Obligations
0%
Other Assets and Liabilities, Net
1%
Total
100%

Sector Allocation

Table Summary
Sector
% of Net Assets
Information Technology
37%
Financials
12%
Communication Services
10%
Consumer Discretionary
9%
Industrials
9%
Health Care
9%
Consumer Staples
4%
Energy
3%
Utilities
2%
Materials
2%
Real Estate
2%

Ten Largest Equity Holdings

Table Summary
Holdings
37.3% of Net Assets
NVIDIA Corp.
7.4%
Apple, Inc.
6.5%
Alphabet, Inc.
5.8%
Microsoft Corp.
4.2%
Amazon.com, Inc.
3.6%
Broadcom, Inc.
2.7%
Micron Technology, Inc.
2.0%
Meta Platforms, Inc.
1.9%
Tesla, Inc.
1.8%
Eli Lilly & Co.
1.4%
C000016413  
Shareholder Report [Line Items]  
Fund Name DWS Equity 500 Index Fund
Class Name Class S
Trading Symbol BTIEX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about DWS Equity 500 Index Fund (the "Fund") for the period January 1, 2026 to June 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund on the Fund's website at dws.com/mutualreports. You can also request this information by contacting us at (800) 728-3337.
Additional Information Phone Number (800) 728-3337
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 14.6667px; font-weight: 300; grid-area: auto; line-height: 17.6px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">dws.com/mutualreports</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Fund
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class S
$13
0.25%Footnote Reference(a)
FootnoteDescription
Footnote(a)
Annualized.

The Fund is a feeder fund which invests all of its investable assets in a master portfolio, Deutsche DWS Equity 500 Index Portfolio. Fund costs reflect the expenses of both the feeder and master fund.

Gross expense ratio as of the latest prospectus: 0.32%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher.

Expenses Paid, Amount $ 13
Expense Ratio, Percent 0.25% [2]
Expenses Represent Both Master and Feeder [Text] The Fund is a feeder fund which invests all of its investable assets in a master portfolio, Deutsche DWS Equity 500 Index Portfolio. Fund costs reflect the expenses of both the feeder and master fund.
AssetsNet $ 426,997,498
Holdings Count | Holding 506
Advisory Fees Paid, Amount $ 105,999
InvestmentCompanyPortfolioTurnover 1.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Net Assets ($)
426,997,498
Number of Portfolio Holdings
506
Portfolio Turnover Rate (%)
1
Total Net Advisory Fees Paid ($)
105,999
Holdings [Text Block]

Asset Allocation

Table Summary
Asset Type
% of Net Assets
Common Stocks
98%
Cash Equivalents
1%
Government & Agency Obligations
0%
Other Assets and Liabilities, Net
1%
Total
100%

Sector Allocation

Table Summary
Sector
% of Net Assets
Information Technology
37%
Financials
12%
Communication Services
10%
Consumer Discretionary
9%
Industrials
9%
Health Care
9%
Consumer Staples
4%
Energy
3%
Utilities
2%
Materials
2%
Real Estate
2%

Ten Largest Equity Holdings

Table Summary
Holdings
37.3% of Net Assets
NVIDIA Corp.
7.4%
Apple, Inc.
6.5%
Alphabet, Inc.
5.8%
Microsoft Corp.
4.2%
Amazon.com, Inc.
3.6%
Broadcom, Inc.
2.7%
Micron Technology, Inc.
2.0%
Meta Platforms, Inc.
1.9%
Tesla, Inc.
1.8%
Eli Lilly & Co.
1.4%
C000016414  
Shareholder Report [Line Items]  
Fund Name DWS Equity 500 Index Fund
Class Name Institutional Class
Trading Symbol BTIIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about DWS Equity 500 Index Fund (the "Fund") for the period January 1, 2026 to June 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund on the Fund's website at dws.com/mutualreports. You can also request this information by contacting us at (800) 728-3337.
Additional Information Phone Number (800) 728-3337
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 14.6667px; font-weight: 300; grid-area: auto; line-height: 17.6px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">dws.com/mutualreports</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Fund
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Institutional Class
$10
0.20%Footnote Reference(a)
FootnoteDescription
Footnote(a)
Annualized.

The Fund is a feeder fund which invests all of its investable assets in a master portfolio, Deutsche DWS Equity 500 Index Portfolio. Fund costs reflect the expenses of both the feeder and master fund.

Gross expense ratio as of the latest prospectus: 0.29%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher.

Expenses Paid, Amount $ 10
Expense Ratio, Percent 0.20% [3]
Expenses Represent Both Master and Feeder [Text] The Fund is a feeder fund which invests all of its investable assets in a master portfolio, Deutsche DWS Equity 500 Index Portfolio. Fund costs reflect the expenses of both the feeder and master fund.
AssetsNet $ 426,997,498
Holdings Count | Holding 506
Advisory Fees Paid, Amount $ 105,999
InvestmentCompanyPortfolioTurnover 1.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Net Assets ($)
426,997,498
Number of Portfolio Holdings
506
Portfolio Turnover Rate (%)
1
Total Net Advisory Fees Paid ($)
105,999
Holdings [Text Block]

Asset Allocation

Table Summary
Asset Type
% of Net Assets
Common Stocks
98%
Cash Equivalents
1%
Government & Agency Obligations
0%
Other Assets and Liabilities, Net
1%
Total
100%

Sector Allocation

Table Summary
Sector
% of Net Assets
Information Technology
37%
Financials
12%
Communication Services
10%
Consumer Discretionary
9%
Industrials
9%
Health Care
9%
Consumer Staples
4%
Energy
3%
Utilities
2%
Materials
2%
Real Estate
2%

Ten Largest Equity Holdings

Table Summary
Holdings
37.3% of Net Assets
NVIDIA Corp.
7.4%
Apple, Inc.
6.5%
Alphabet, Inc.
5.8%
Microsoft Corp.
4.2%
Amazon.com, Inc.
3.6%
Broadcom, Inc.
2.7%
Micron Technology, Inc.
2.0%
Meta Platforms, Inc.
1.9%
Tesla, Inc.
1.8%
Eli Lilly & Co.
1.4%
[1] Annualized.
[2] Annualized.
[3] Annualized.