| Form N-CSR Cover | 6 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | DEUTSCHE DWS VARIABLE SERIES I |
| Entity Central Index Key | 0000764797 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 6 Months Ended |
| Jun. 30, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | DEUTSCHE DWS VARIABLE SERIES I |
| Entity Central Index Key | 0000764797 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| C000017180 | |
| Shareholder Report [Line Items] | |
| Fund Name | DWS Capital Growth VIP |
| Class Name | Class A |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about DWS Capital Growth VIP ("the Fund") for the period January 1, 2024 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund on the Fund's website at dws.com/vipreports |
| Additional Information Phone Number | (800) 728-3337 |
| Additional Information Website | dws.com/vipreports</span>" id="sjs-B18"><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;">dws.com/vipreports</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Cost of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $26 0.49% Gross expense ratio as of the latest prospectus: 0.49%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher. Fund costs do not reflect any fees or sales charges imposed by a variable contract for which the Fund is an investment option. |
| Expenses Paid, Amount | $ 26 |
| Expense Ratio, Percent | 0.49% |
| AssetsNet | $ 1,062,451,079 |
| Holdings Count | Holding | 77 |
| Advisory Fees Paid, Amount | $ 1,886,004 |
| InvestmentCompanyPortfolioTurnover | 8% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets ($) 1,062,451,079 Number of Portfolio Holdings 77 Portfolio Turnover Rate (%) 8 Total Net Advisory Fees Paid ($) 1,886,004 |
| Holdings [Text Block] | Asset Allocation Asset Type % of Net Assets Common Stocks 99% Cash Equivalents 1% Other Assets and Liabilities, Net 0% Total 100% |
| C000017184 | |
| Shareholder Report [Line Items] | |
| Fund Name | DWS Core Equity VIP |
| Class Name | Class A |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about DWS Core Equity VIP ("the Fund") for the period January 1, 2024 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund on the Fund's website at dws.com/vipreports |
| Additional Information Phone Number | (800) 728-3337 |
| Additional Information Website | dws.com/vipreports</span>" id="sjs-B36"><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;">dws.com/vipreports</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Cost of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $32 0.60% Gross expense ratio as of the latest prospectus: 0.61%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher. Fund costs do not reflect any fees or sales charges imposed by a variable contract for which the Fund is an investment option. |
| Expenses Paid, Amount | $ 32 |
| Expense Ratio, Percent | 0.60% |
| AssetsNet | $ 116,226,065 |
| Holdings Count | Holding | 109 |
| Advisory Fees Paid, Amount | $ 222,666 |
| InvestmentCompanyPortfolioTurnover | 8% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets ($) 116,226,065 Number of Portfolio Holdings 109 Portfolio Turnover Rate (%) 8 Total Net Advisory Fees Paid ($) 222,666 |
| Holdings [Text Block] | Asset Allocation Asset Type % of Net Assets Common Stocks 100% Cash Equivalents 0% Other Assets and Liabilities, Net 0% Total 100% |
| C000017188 | |
| Shareholder Report [Line Items] | |
| Fund Name | DWS CROCI International VIP |
| Class Name | Class A |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about DWS CROCI International VIP ("the Fund") for the period January 1, 2024 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund on the Fund's website at dws.com/vipreports |
| Additional Information Phone Number | (800) 728-3337 |
| Additional Information Website | dws.com/vipreports</span>" id="sjs-B54"><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;">dws.com/vipreports</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Cost of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $42 0.84% Gross expense ratio as of the latest prospectus: 0.95%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher. Fund costs do not reflect any fees or sales charges imposed by a variable contract for which the Fund is an investment option. |
| Expenses Paid, Amount | $ 42 |
| Expense Ratio, Percent | 0.84% |
| AssetsNet | $ 71,637,365 |
| Holdings Count | Holding | 63 |
| Advisory Fees Paid, Amount | $ 197,893 |
| InvestmentCompanyPortfolioTurnover | 30% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets ($) 71,637,365 Number of Portfolio Holdings 63 Portfolio Turnover Rate (%) 30 Total Net Advisory Fees Paid ($) 197,893 |
| C000017182 | |
| Shareholder Report [Line Items] | |
| Fund Name | DWS Global Small Cap VIP |
| Class Name | Class A |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about DWS Global Small Cap VIP ("the Fund") for the period January 1, 2024 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund on the Fund's website at dws.com/vipreports |
| Additional Information Phone Number | (800) 728-3337 |
| Additional Information Website | dws.com/vipreports</span>" id="sjs-B71"><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;">dws.com/vipreports</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Cost of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $43 0.87% Gross expense ratio as of the latest prospectus: 1.09%. See prospectus for any contractual or voluntary waivers; without a waiver, costs would have been higher. Fund costs do not reflect any fees or sales charges imposed by a variable contract for which the Fund is an investment option. |
| Expenses Paid, Amount | $ 43 |
| Expense Ratio, Percent | 0.87% |
| AssetsNet | $ 61,592,496 |
| Holdings Count | Holding | 124 |
| Advisory Fees Paid, Amount | $ 185,450 |
| InvestmentCompanyPortfolioTurnover | 14% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets ($) 61,592,496 Number of Portfolio Holdings 124 Portfolio Turnover Rate (%) 14 Total Net Advisory Fees Paid ($) 185,450 |
| Shareholder Report, Holdings (Details) | Jun. 30, 2024 |
| C000017180 | NVIDIA Corp. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11% |
| C000017180 | Microsoft Corp. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.90% |
| C000017180 | Apple, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.60% |
| C000017180 | Alphabet, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.40% |
| C000017180 | Amazon.com, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.80% |
| C000017180 | Progressive Corp. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.20% |
| C000017180 | Meta Platforms, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000017180 | Synopsys, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.20% |
| C000017180 | Visa, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.90% |
| C000017180 | Mastercard, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.80% |
| C000017180 | SectorInformation Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 46% |
| C000017180 | SectorCommunication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13% |
| C000017180 | SectorHealth Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12% |
| C000017180 | SectorFinancials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10% |
| C000017180 | SectorConsumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8% |
| C000017180 | SectorIndustrials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5% |
| C000017180 | SectorConsumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000017180 | SectorReal Estate | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| C000017180 | SectorMaterials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| C000017180 | AssetCommon Stocks | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 99% |
| C000017180 | AssetCash Equivalents | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| C000017180 | Asset Other Net Line | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| C000017184 | NVIDIA Corp. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.30% |
| C000017184 | Microsoft Corp. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.80% |
| C000017184 | Apple, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8% |
| C000017184 | Alphabet, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.20% |
| C000017184 | Amazon.com, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.90% |
| C000017184 | Meta Platforms, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000017184 | Visa, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.90% |
| C000017184 | JPMorgan Chase & Co. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.90% |
| C000017184 | Oracle Corp. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.30% |
| C000017184 | QUALCOMM, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.90% |
| C000017184 | SectorInformation Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 31% |
| C000017184 | SectorCommunication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10% |
| C000017184 | SectorHealth Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12% |
| C000017184 | SectorFinancials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13% |
| C000017184 | SectorConsumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9% |
| C000017184 | SectorIndustrials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10% |
| C000017184 | SectorConsumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5% |
| C000017184 | SectorReal Estate | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| C000017184 | SectorMaterials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| C000017184 | SectorEnergy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4% |
| C000017184 | SectorUtilities | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| C000017184 | AssetCommon Stocks | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 100% |
| C000017184 | AssetCash Equivalents | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| C000017184 | Asset Other Net Line | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| C000017188 | Oversea-Chinese Banking Corp. Ltd. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.70% |
| C000017188 | Shionogi & Co. Ltd. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.10% |
| C000017188 | Nintendo Co. Ltd. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.60% |
| C000017188 | Lloyds Banking Group PLC | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.60% |
| C000017188 | Stellantis NV | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.50% |
| C000017188 | Ono Pharmaceutical Co. Ltd. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.30% |
| C000017188 | STMicroelectronics NV | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.20% |
| C000017188 | Holcim AG | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.10% |
| C000017188 | Sekisui House Ltd. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.80% |
| C000017188 | Cie Financiere Richemont SA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.80% |
| C000017188 | Country Other Line | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7% |
| C000017188 | SectorInformation Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6% |
| C000017188 | SectorCommunication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9% |
| C000017188 | SectorHealth Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 22% |
| C000017188 | SectorFinancials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 23% |
| C000017188 | SectorConsumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 14% |
| C000017188 | SectorIndustrials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8% |
| C000017188 | SectorConsumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| C000017188 | SectorMaterials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9% |
| C000017188 | SectorEnergy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4% |
| C000017188 | SectorUtilities | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| C000017188 | Japan | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 27% |
| C000017188 | United Kingdom | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12% |
| C000017188 | Switzerland | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12% |
| C000017188 | France | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11% |
| C000017188 | Singapore | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8% |
| C000017188 | Germany | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5% |
| C000017188 | Australia | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5% |
| C000017188 | Netherlands | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5% |
| C000017188 | Luxembourg | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4% |
| C000017188 | Spain | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000017188 | AssetCommon Stocks | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 98% |
| C000017188 | AssetCash Equivalents | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| C000017188 | Asset Other Net Line | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| C000017188 | AssetPreferred Stocks | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| C000017182 | Modine Manufacturing Co. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.10% |
| C000017182 | TopBuild Corp. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| C000017182 | Rush Enterprises, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| C000017182 | Casey's General Stores, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.90% |
| C000017182 | Thermon Group Holdings, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.80% |
| C000017182 | Buzzi SpA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.80% |
| C000017182 | Synovus Financial Corp. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.80% |
| C000017182 | Builders FirstSource, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.70% |
| C000017182 | Systena Corp. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.70% |
| C000017182 | SkyWest, Inc. | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.70% |
| C000017182 | Country Other Line | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6% |
| C000017182 | Korea | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000017182 | SectorInformation Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12% |
| C000017182 | SectorCommunication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000017182 | SectorHealth Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9% |
| C000017182 | SectorFinancials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 14% |
| C000017182 | SectorConsumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 14% |
| C000017182 | SectorIndustrials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 19% |
| C000017182 | SectorConsumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5% |
| C000017182 | SectorReal Estate | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7% |
| C000017182 | SectorMaterials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8% |
| C000017182 | SectorEnergy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5% |
| C000017182 | SectorUtilities | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000017182 | Japan | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7% |
| C000017182 | United Kingdom | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7% |
| C000017182 | Switzerland | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000017182 | France | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| C000017182 | Germany | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| C000017182 | Australia | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4% |
| C000017182 | United States | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 61% |
| C000017182 | Canada | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000017182 | Italy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| C000017182 | AssetCommon Stocks | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 99% |
| C000017182 | AssetCash Equivalents | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| C000017182 | Asset Other Net Line | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
