| Shareholder Report | 6 Months Ended |
| Jun. 30, 2024 USD ($) Holding |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS/A |
| Amendment Flag | false |
| Registrant Name | NORTHWESTERN MUTUAL SERIES FUND INC |
| Entity Central Index Key | 0000742212 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| C000000078 | |
| Shareholder Report [Line Items] | |
| Fund Name | INDEX 500 STOCK PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Index 500 Stock Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B17"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B18" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Index 500 Stock Portfolio $10 0.19% |
| Expenses Paid, Amount | $ 10 |
| Expense Ratio, Percent | 0.19% |
| AssetsNet | $ 6,191,682,000 |
| Holdings Count | Holding | 503 |
| InvestmentCompanyPortfolioTurnover | 1% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $6,191,682 # of Portfolio Holdings (Derivatives not included as applicable) 503 Portfolio Turnover Rate 1% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 1.0% Real Estate 2.1% Materials 2.1% Utilities 2.2% Energy 3.6% Consumer Staples 5.7% Industrials 8.1% Communication Services 9.3% Consumer Discretionary 9.9% Health Care 11.6% Financials 12.3% Information Technology 32.1% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Microsoft Corp. 7.2% NVIDIA Corp. 6.6% Apple, Inc. 6.6% Alphabet, Inc., Various 4.2% Amazon.com, Inc. 3.8% Meta Platforms, Inc. - Class A 2.4% Berkshire Hathaway, Inc. - Class B 1.6% Eli Lilly & Co. 1.6% Broadcom, Inc. 1.5% JPMorgan Chase & Co. 1.3% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B28" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000050283 | |
| Shareholder Report [Line Items] | |
| Fund Name | MULTI-SECTOR BOND PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Multi-Sector Bond Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B36"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B37" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Multi-Sector Bond Portfolio $38 0.75% |
| Expenses Paid, Amount | $ 38 |
| Expense Ratio, Percent | 0.75% |
| AssetsNet | $ 1,257,981,000 |
| Holdings Count | Holding | 920 |
| InvestmentCompanyPortfolioTurnover | 18% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $1,257,981 # of Portfolio Holdings (Derivatives not included as applicable) 920 Portfolio Turnover Rate 18% |
| Holdings [Text Block] | Asset Type Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets - Convertible Corporate Bonds 0.0% Common Stocks 0.1% Municipal Bonds 0.5% Bank Loan Obligations 2.9% Governments 22.2% Structured Products 30.6% Corporate Bonds 44.9% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Uniform Mortgage Backed Security TBA, Various 10.2% Citigroup Global Markets, Inc. Repurchase Agreement, Various 6.2% US Treasury, Various 6.1% BNP Paribas SA Repurchase Agreement, 5.39%, 7/1/24 5.7% Canadian Imperial Bank of Commerce Repurchase Agreement, Various 4.1% Federal Home Loan Mortgage Corp., Various 3.4% Saudi International Bond, Various 1.5% Petroleos Mexicanos, Various 1.2% European Union, 3%, 12/4/34 1.1% United Mexican States, Various 1.0% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B47" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000050277 | |
| Shareholder Report [Line Items] | |
| Fund Name | LARGE CAP BLEND PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Large Cap Blend Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B55"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B56" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Large Cap Blend Portfolio $40 0.74% |
| Expenses Paid, Amount | $ 40 |
| Expense Ratio, Percent | 0.74% |
| AssetsNet | $ 164,518,000 |
| Holdings Count | Holding | 51 |
| InvestmentCompanyPortfolioTurnover | 30% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $164,518 # of Portfolio Holdings (Derivatives not included as applicable) 51 Portfolio Turnover Rate 30% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets - Real Estate 1.2% Consumer Staples 1.2% Materials 1.9% Utilities 3.1% Energy 4.8% Communication Services 6.7% Industrials 10.2% Financials 11.1% Consumer Discretionary 11.3% Health Care 13.4% Information Technology 37.5% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Microsoft Corp. 9.9% Apple, Inc. 8.0% NVIDIA Corp. 7.5% Amazon.com, Inc. 4.5% Alphabet, Inc. - Class A 3.4% Meta Platforms, Inc. - Class A 3.3% Exxon Mobil Corp. 2.6% Wells Fargo & Co. 2.6% Regeneron Pharmaceuticals, Inc. 2.4% UnitedHealth Group, Inc. 2.4% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B66" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000084 | |
| Shareholder Report [Line Items] | |
| Fund Name | SMALL CAP VALUE PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Small Cap Value Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B74"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B75" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Small Cap Value Portfolio $43 0.87% |
| Expenses Paid, Amount | $ 43 |
| Expense Ratio, Percent | 0.87% |
| AssetsNet | $ 547,793,000 |
| Holdings Count | Holding | 203 |
| InvestmentCompanyPortfolioTurnover | 17% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $547,793 # of Portfolio Holdings (Derivatives not included as applicable) 203 Portfolio Turnover Rate 17% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 3.7% Communication Services 1.5% Consumer Staples 2.0% Utilities 4.1% Materials 4.9% Information Technology 6.3% Health Care 8.4% Energy 8.9% Real Estate 10.0% Consumer Discretionary 10.8% Industrials 13.8% Financials 25.6% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) PennyMac Financial Services, Inc. 1.7% Pinnacle Financial Partners, Inc. 1.6% Matador Resources Co. 1.5% Meritage Homes Corp. 1.2% Popular, Inc. 1.2% Houlihan Lokey, Inc. 1.1% Strategic Education, Inc. 1.1% Select Medical Holdings Corp. 1.1% TechnipFMC PLC 1.1% Terreno Realty Corp. 1.1% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B85" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000081 | |
| Shareholder Report [Line Items] | |
| Fund Name | HIGH YIELD BOND PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the High Yield Bond Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B93"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B94" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment High Yield Bond Portfolio $23 0.46% |
| Expenses Paid, Amount | $ 23 |
| Expense Ratio, Percent | 0.46% |
| AssetsNet | $ 677,148,000 |
| Holdings Count | Holding | 523 |
| InvestmentCompanyPortfolioTurnover | 14% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $677,148 # of Portfolio Holdings (Derivatives not included as applicable) 523 Portfolio Turnover Rate 14% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 4.8% Diversified 0.2% Utilities 2.4% Basic Materials 3.3% Technology 10.5% Energy 10.6% Financial 10.9% Communications 11.8% Consumer, Non-Cyclical 12.7% Industrial 13.0% Consumer, Cyclical 19.8% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Ford Motor Credit Co. LLC, Various 2.3% CCO Holdings LLC / CCO Holdings Capital Corp., Various 1.9% HUB International, Ltd., Various 1.7% TransDigm, Inc., Various 1.6% Tenet Healthcare Corp., Various 1.1% CSC Holdings LLC, Various 1.1% EQM Midstream Partners LP, Various 1.1% Medline Borrower LP, Various 1.1% Garda World Security Corp., Various 1.1% Clarios Global LP / Clarios US Finance Co., Various 1.0% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B104" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000085 | |
| Shareholder Report [Line Items] | |
| Fund Name | MID CAP GROWTH STOCK PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Mid Cap Growth Stock Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B112"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B113" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Mid Cap Growth Stock Portfolio $27 0.54% |
| Expenses Paid, Amount | $ 27 |
| Expense Ratio, Percent | 0.54% |
| AssetsNet | $ 1,014,798,000 |
| Holdings Count | Holding | 93 |
| InvestmentCompanyPortfolioTurnover | 38% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $1,014,798 # of Portfolio Holdings (Derivatives not included as applicable) 93 Portfolio Turnover Rate 38% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets -% Materials 1.0% Real Estate 1.1% Communication Services 2.5% Utilities 2.8% Consumer Staples 3.1% Energy 3.8% Financials 11.3% Consumer Discretionary 14.7% Industrials 16.0% Health Care 18.3% Information Technology 25.4% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Datadog, Inc. - Class A 2.8% CyberArk Software, Ltd. 2.3% Targa Resources Corp. 2.3% DraftKings, Inc. - Class A 2.3% Monolithic Power Systems, Inc. 2.3% PTC, Inc. 2.0% WEX, Inc. 2.0% Dexcom, Inc. 2.0% NVR, Inc. 1.9% Fair Isaac Corp. 1.8% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B123" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000076 | |
| Shareholder Report [Line Items] | |
| Fund Name | DOMESTIC EQUITY PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Domestic Equity Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B131"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B132" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Domestic Equity Portfolio $25 0.50% |
| Expenses Paid, Amount | $ 25 |
| Expense Ratio, Percent | 0.50% |
| AssetsNet | $ 1,039,415,000 |
| Holdings Count | Holding | 33 |
| InvestmentCompanyPortfolioTurnover | 16% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $1,039,415 # of Portfolio Holdings (Derivatives not included as applicable) 33 Portfolio Turnover Rate 16% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 1.4% Real Estate 3.0% Utilities 3.2% Materials 3.4% Energy 5.9% Communication Services 6.0% Consumer Staples 7.9% Consumer Discretionary 9.3% Industrials 12.5% Financials 15.2% Information Technology 15.5% Health Care 16.7% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Oracle Corp. 3.7% The TJX Cos., Inc. 3.7% Honeywell International, Inc. 3.5% Motorola Solutions, Inc. 3.4% DuPont de Nemours, Inc. 3.4% Fidelity National Information Services, Inc. 3.3% Duke Energy Corp. 3.2% Verizon Communications, Inc. 3.2% Truist Financial Corp. 3.2% Dover Corp. 3.1% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B142" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000050279 | |
| Shareholder Report [Line Items] | |
| Fund Name | INDEX 600 STOCK PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Index 600 Stock Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B150"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B151" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Index 600 Stock Portfolio $13 0.27% |
| Expenses Paid, Amount | $ 13 |
| Expense Ratio, Percent | 0.27% |
| AssetsNet | $ 438,644,000 |
| Holdings Count | Holding | 604 |
| InvestmentCompanyPortfolioTurnover | 9% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $438,644 # of Portfolio Holdings (Derivatives not included as applicable) 604 Portfolio Turnover Rate 9% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 0.7% Utilities 2.0% Communication Services 2.8% Consumer Staples 3.4% Energy 5.2% Materials 5.8% Real Estate 7.2% Health Care 10.3% Information Technology 12.9% Consumer Discretionary 14.2% Industrials 17.3% Financials 18.2% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Abercrombie & Fitch Co. 0.8% Fabrinet 0.7% Ensign Group, Inc. 0.6% SPS Commerce, Inc. 0.6% Allegheny Technologies, Inc. 0.6% Comerica, Inc. 0.6% Robert Half International, Inc. 0.6% SPX Technologies, Inc. 0.6% Mueller Industries, Inc. 0.5% Glaukos Corp. 0.5% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B161" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000087 | |
| Shareholder Report [Line Items] | |
| Fund Name | INTERNATIONAL EQUITY PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the International Equity Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B169"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B170" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment International Equity Portfolio $34 0.68% |
| Expenses Paid, Amount | $ 34 |
| Expense Ratio, Percent | 0.68% |
| AssetsNet | $ 1,901,407,000 |
| Holdings Count | Holding | 81 |
| InvestmentCompanyPortfolioTurnover | 12% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $1,901,407 # of Portfolio Holdings (Derivatives not included as applicable) 81 Portfolio Turnover Rate 12% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 2.0% Real Estate 1.4% Communication Services 4.4% Energy 6.6% Information Technology 7.5% Consumer Staples 8.1% Industrials 9.5% Materials 11.3% Consumer Discretionary 11.9% Health Care 14.1% Financials 23.2% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Novartis AG 3.3% Sanofi 3.1% BNP Paribas SA 3.1% Holcim, Ltd. 3.0% Banco Santander SA 3.0% Johnson Controls International PLC 3.0% GSK PLC 2.8% TotalEnergies SE 2.7% UBS Group AG 2.6% Taiwan Semiconductor Manufacturing Co., Ltd. 2.4% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B180" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000091 | |
| Shareholder Report [Line Items] | |
| Fund Name | GROWTH STOCK PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Growth Stock Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B188"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B189" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Growth Stock Portfolio $24 0.42% |
| Expenses Paid, Amount | $ 24 |
| Expense Ratio, Percent | 0.42% |
| AssetsNet | $ 1,295,455,000 |
| Holdings Count | Holding | 75 |
| InvestmentCompanyPortfolioTurnover | 4% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $1,295,455 # of Portfolio Holdings (Derivatives not included as applicable) 75 Portfolio Turnover Rate 4% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 0.5% Energy 0.3% Utilities 0.7% Materials 0.8% Consumer Staples 1.5% Industrials 1.8% Financials 8.8% Health Care 11.3% Consumer Discretionary 15.1% Communication Services 16.5% Information Technology 42.7% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) NVIDIA Corp. 13.5% Microsoft Corp. 10.0% Amazon.com, Inc. 9.0% Alphabet, Inc., Various 8.6% Apple, Inc. 7.7% Meta Platforms, Inc. - Class A 4.8% Eli Lilly & Co. 4.0% Visa, Inc. - Class A 2.8% Mastercard, Inc. - Class A 2.4% ServiceNow, Inc. 2.2% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B199" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000088 | |
| Shareholder Report [Line Items] | |
| Fund Name | MID CAP VALUE PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Mid Cap Value Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B207"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B208" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Mid Cap Value Portfolio $36 0.72% |
| Expenses Paid, Amount | $ 36 |
| Expense Ratio, Percent | 0.72% |
| AssetsNet | $ 623,462,000 |
| Holdings Count | Holding | 101 |
| InvestmentCompanyPortfolioTurnover | 29% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $623,462 # of Portfolio Holdings (Derivatives not included as applicable) 101 Portfolio Turnover Rate 29% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 2.0% Communication Services 1.5% Consumer Discretionary 3.7% Materials 4.2% Real Estate 5.8% Energy 6.0% Information Technology 7.1% Consumer Staples 11.3% Utilities 12.0% Industrials 14.1% Health Care 14.8% Financials 17.5% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Zimmer Biomet Holdings, Inc. 3.0% The Bank of New York Mellon Corp. 2.2% Conagra Brands, Inc. 2.1% Enterprise Products Partners LP 2.0% Henry Schein, Inc. 1.9% Northern Trust Corp. 1.9% Koninklijke Ahold Delhaize NV 1.9% Willis Towers Watson PLC 1.9% Edison International 1.8% Quest Diagnostics, Inc. 1.8% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B218" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000082 | |
| Shareholder Report [Line Items] | |
| Fund Name | SELECT BOND PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Select Bond Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B226"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B227" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Select Bond Portfolio $15 0.31% |
| Expenses Paid, Amount | $ 15 |
| Expense Ratio, Percent | 0.31% |
| AssetsNet | $ 2,806,791,000 |
| Holdings Count | Holding | 1,029 |
| InvestmentCompanyPortfolioTurnover | 128% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $2,806,791 # of Portfolio Holdings (Derivatives not included as applicable) 1,029 Portfolio Turnover Rate 128% |
| Holdings [Text Block] | Asset Type Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets - Municipal Bonds 0.3% Governments 23.3% Corporate Bonds 25.8% Structured Products 52.4% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) US Treasury, Various 21.8% Federal National Mortgage Association, Various 18.0% Federal Home Loan Mortgage Corp., Various 4.5% Uniform Mortgage Backed Security TBA, Various 1.8% Government National Mortgage Association, Various 1.5% Government National Mortgage Association TBA, 6.5%, 7/15/54 1.3% Wells Fargo & Co., Various 1.0% John Deere Capital Corp., Various 0.9% Morgan Stanley, Various 0.9% Bank of America Corp., Various 0.8% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B237" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000086 | |
| Shareholder Report [Line Items] | |
| Fund Name | INTERNATIONAL GROWTH PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the International Growth Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B245"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B246" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment International Growth Portfolio $31 0.61% |
| Expenses Paid, Amount | $ 31 |
| Expense Ratio, Percent | 0.61% |
| AssetsNet | $ 1,058,591,000 |
| Holdings Count | Holding | 69 |
| InvestmentCompanyPortfolioTurnover | 11% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $1,058,591 # of Portfolio Holdings (Derivatives not included as applicable) 69 Portfolio Turnover Rate 11% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 2.9% Communication Services 0.3% Energy 0.7% Consumer Staples 1.9% Health Care 7.4% Materials 9.2% Consumer Discretionary 9.7% Financials 14.5% Information Technology 24.1% Industrials 29.3% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) ASML Holding NV 7.8% Novo Nordisk A/S - Class B 6.5% SAP SE 4.4% Linde PLC 3.9% Safran SA 3.7% Atlas Copco AB - Class A 3.7% LVMH Moet Hennessy Louis Vuitton SE 3.5% Taiwan Semiconductor Manufacturing Co., Ltd. 3.4% CRH PLC 3.0% Keyence Corp. 2.9% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B256" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000090 | |
| Shareholder Report [Line Items] | |
| Fund Name | FOCUSED APPRECIATION PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Focused Appreciation Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B264"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B265" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Focused Appreciation Portfolio $33 0.61% |
| Expenses Paid, Amount | $ 33 |
| Expense Ratio, Percent | 0.61% |
| AssetsNet | $ 1,379,557,000 |
| Holdings Count | Holding | 37 |
| InvestmentCompanyPortfolioTurnover | 6% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $1,379,557 # of Portfolio Holdings (Derivatives not included as applicable) 37 Portfolio Turnover Rate 6% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 2.8% Consumer Staples 2.3% Industrials 6.8% Financials 8.7% Health Care 13.4% Consumer Discretionary 15.3% Communication Services 22.3% Information Technology 28.4% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) NVIDIA Corp. 7.9% Meta Platforms, Inc. - Class A 7.3% Alphabet, Inc., Various 6.9% Amazon.com, Inc. 6.0% Tesla, Inc. 5.9% Microsoft Corp. 5.2% Netflix, Inc. 5.2% The Boeing Co. 4.9% Visa, Inc. - Class A 4.8% Oracle Corp. 4.8% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B275" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000075 | |
| Shareholder Report [Line Items] | |
| Fund Name | LARGE CAP CORE STOCK PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Large Cap Core Stock Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B283"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B284" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Large Cap Core Stock Portfolio $23 0.43% |
| Expenses Paid, Amount | $ 23 |
| Expense Ratio, Percent | 0.43% |
| AssetsNet | $ 735,095,000 |
| Holdings Count | Holding | 127 |
| InvestmentCompanyPortfolioTurnover | 32% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $735,095 # of Portfolio Holdings (Derivatives not included as applicable) 127 Portfolio Turnover Rate 32% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 0.5% Real Estate 1.5% Materials 2.1% Utilities 2.5% Consumer Staples 3.6% Energy 4.8% Industrials 8.0% Communication Services 9.9% Consumer Discretionary 11.4% Financials 13.0% Health Care 13.3% Information Technology 29.4% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Microsoft Corp. 6.5% Apple, Inc. 6.4% Amazon.com, Inc. 5.5% Alphabet, Inc. - Class A 5.2% NVIDIA Corp. 4.9% Eli Lilly & Co. 2.1% Exxon Mobil Corp. 2.1% Adobe, Inc. 1.9% The TJX Cos., Inc. 1.9% Berkshire Hathaway, Inc. - Class B 1.8% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B294" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000050276 | |
| Shareholder Report [Line Items] | |
| Fund Name | INFLATION PROTECTION PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Inflation Protection Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B302"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B303" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Inflation Protection Portfolio $22 0.45% |
| Expenses Paid, Amount | $ 22 |
| Expense Ratio, Percent | 0.45% |
| AssetsNet | $ 411,975,000 |
| Holdings Count | Holding | 122 |
| InvestmentCompanyPortfolioTurnover | 22% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $411,975 # of Portfolio Holdings (Derivatives not included as applicable) 122 Portfolio Turnover Rate 22% |
| Holdings [Text Block] | Asset Type Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 8.7% Municipal Bonds 0.4% Corporate Bonds 6.1% Structured Products 15.7% Governments 69.1% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) US Treasury Inflation Index Bond, Various 54.0% Federal National Mortgage Association, Various 8.3% Federal Home Loan Mortgage Corp., Various 4.9% Canadian Government Bond, Various 3.7% Barton Capital Corp. 2.8% Government National Mortgage Association, Various 2.6% LMA SA / LMA Americas LLC, Various 2.2% Chevron Corp. 1.8% Deutsche Bundesrepublik Inflation Linked Bond, 0.1%, 4/15/26 1.7% Tennessee Valley Authority, Various 1.6% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B313" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000077 | |
| Shareholder Report [Line Items] | |
| Fund Name | EQUITY INCOME PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Equity Income Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B321"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B322" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Equity Income Portfolio $29 0.57% |
| Expenses Paid, Amount | $ 29 |
| Expense Ratio, Percent | 0.57% |
| AssetsNet | $ 726,329,000 |
| Holdings Count | Holding | 114 |
| InvestmentCompanyPortfolioTurnover | 11% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $726,329 # of Portfolio Holdings (Derivatives not included as applicable) 114 Portfolio Turnover Rate 11% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 1.2% Materials 3.0% Consumer Discretionary 3.0% Real Estate 4.2% Communication Services 4.5% Utilities 6.0% Consumer Staples 8.6% Energy 8.9% Information Technology 11.1% Industrials 12.5% Health Care 16.5% Financials 20.5% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Elevance Health, Inc. 2.7% QUALCOMM, Inc. 2.4% News Corp., Various 2.3% Wells Fargo & Co. 2.3% TotalEnergies SE, ADR 2.3% The Southern Co. 2.2% Chubb, Ltd. 2.0% American International Group, Inc. 2.0% MetLife, Inc. 1.8% General Electric Co. 1.8% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B332" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000050278 | |
| Shareholder Report [Line Items] | |
| Fund Name | RESEARCH INTERNATIONAL CORE PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Research International Core Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B340"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B341" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Research International Core Portfolio $37 0.73% |
| Expenses Paid, Amount | $ 37 |
| Expense Ratio, Percent | 0.73% |
| AssetsNet | $ 862,998,000 |
| Holdings Count | Holding | 109 |
| InvestmentCompanyPortfolioTurnover | 6% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $862,998 # of Portfolio Holdings (Derivatives not included as applicable) 109 Portfolio Turnover Rate 6% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 1.9% Real Estate 1.1% Communication Services 2.5% Utilities 2.5% Energy 5.1% Consumer Staples 6.8% Materials 9.2% Consumer Discretionary 9.4% Information Technology 10.4% Health Care 12.7% Industrials 18.5% Financials 19.9% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Novo Nordisk A/S - Class B 3.9% Schneider Electric SE 3.6% Linde PLC 3.2% Hitachi, Ltd. 2.8% Roche Holding AG 2.5% LVMH Moet Hennessy Louis Vuitton SE 2.3% Nestle SA 2.2% NatWest Group PLC 1.9% TotalEnergies SE 1.7% Euronext NV 1.6% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B351" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000050281 | |
| Shareholder Report [Line Items] | |
| Fund Name | SHORT-TERM BOND PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Short-Term Bond Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B359"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B360" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Short-Term Bond Portfolio $20 0.39% |
| Expenses Paid, Amount | $ 20 |
| Expense Ratio, Percent | 0.39% |
| AssetsNet | $ 383,135,000 |
| Holdings Count | Holding | 799 |
| InvestmentCompanyPortfolioTurnover | 57% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $383,135 # of Portfolio Holdings (Derivatives not included as applicable) 799 Portfolio Turnover Rate 57% |
| Holdings [Text Block] | Asset Type Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 2.3% Governments 24.4% Structured Products 29.4% Corporate Bonds 43.9% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) US Treasury, Various 22.6% Federal National Mortgage Association, Various 3.1% Federal Home Loan Mortgage Corp., Various 1.2% US Treasury Inflation Index Bond, 2.375%, 10/15/28 1.0% AbbVie, Inc., Various 0.9% Crown Castle, Inc., Various 0.9% Government National Mortgage Association, Various 0.7% JPMorgan Chase & Co., Various 0.6% The Goldman Sachs Group, Inc., Various 0.6% VF Corp., Various 0.6% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B370" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000089 | |
| Shareholder Report [Line Items] | |
| Fund Name | INDEX 400 STOCK PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Index 400 Stock Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B378"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B379" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Index 400 Stock Portfolio $13 0.25% |
| Expenses Paid, Amount | $ 13 |
| Expense Ratio, Percent | 0.25% |
| AssetsNet | $ 1,334,984,000 |
| Holdings Count | Holding | 401 |
| InvestmentCompanyPortfolioTurnover | 9% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $1,334,984 # of Portfolio Holdings (Derivatives not included as applicable) 401 Portfolio Turnover Rate 9% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 1.0% Communication Services 1.5% Utilities 2.5% Consumer Staples 4.6% Energy 5.9% Materials 6.5% Real Estate 7.0% Health Care 9.2% Information Technology 9.4% Consumer Discretionary 14.6% Financials 15.7% Industrials 22.1% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Pure Storage, Inc. 0.7% Carlisle Cos., Inc. 0.7% Williams-Sonoma, Inc. 0.7% EMCOR Group, Inc. 0.6% Lennox International, Inc. 0.6% Illumina, Inc. 0.6% Reliance, Inc. 0.6% BioMarin Pharmaceutical, Inc. 0.6% Burlington Stores, Inc. 0.6% Manhattan Associates, Inc. 0.6% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B389" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000050275 | |
| Shareholder Report [Line Items] | |
| Fund Name | LARGE COMPANY VALUE PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Large Company Value Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B397"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B398" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Large Company Value Portfolio $37 0.74% |
| Expenses Paid, Amount | $ 37 |
| Expense Ratio, Percent | 0.74% |
| AssetsNet | $ 148,378,000 |
| Holdings Count | Holding | 74 |
| InvestmentCompanyPortfolioTurnover | 21% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $148,378 # of Portfolio Holdings (Derivatives not included as applicable) 74 Portfolio Turnover Rate 21% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 2.0% Consumer Discretionary 1.2% Real Estate 1.5% Communication Services 3.2% Materials 3.5% Utilities 6.5% Energy 8.1% Information Technology 9.2% Industrials 11.1% Consumer Staples 13.1% Financials 19.2% Health Care 21.4% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Johnson & Johnson 4.5% Medtronic PLC 4.2% Zimmer Biomet Holdings, Inc. 3.6% JPMorgan Chase & Co. 3.2% Exxon Mobil Corp. 2.6% Duke Energy Corp. 2.5% Norfolk Southern Corp. 2.3% United Parcel Service, Inc. - Class B 2.3% The Bank of New York Mellon Corp. 2.2% Analog Devices, Inc. 2.0% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B408" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000050282 | |
| Shareholder Report [Line Items] | |
| Fund Name | LONG-TERM U.S. GOVERNMENT BOND PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Long-Term U.S. Government Bond Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B416"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B417" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Long-Term U.S. Government Bond Portfolio $126 2.60% |
| Expenses Paid, Amount | $ 126 |
| Expense Ratio, Percent | 2.60% |
| AssetsNet | $ 115,452,000 |
| Holdings Count | Holding | 99 |
| InvestmentCompanyPortfolioTurnover | 10% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $115,452 # of Portfolio Holdings (Derivatives not included as applicable) 99 Portfolio Turnover Rate 10% |
| Holdings [Text Block] | Asset Type Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets - Corporate Bonds 0.3% Structured Products 22.5% Governments 125.5% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) US Treasury, Various 114.3% Citigroup Global Markets, Inc. Repurchase Agreement, Various 17.8% Uniform Mortgage Backed Security TBA, Various 10.0% BNP Paribas SA Repurchase Agreement, 5.4%, 7/1/24 10.0% Deutsche Bank AG Repurchase Agreement, 5.41%, 7/1/24 8.0% US Treasury Inflation Index Bond, Various 7.9% Resolution Funding Corp. Stripped, Various 3.5% Federal Home Loan Mortgage Corp., Series 4092, Class AY, 3%, 8/15/32 1.8% Federal Home Loan Mortgage Corp., Series 4387, Class AZ, 4%, 9/15/44 1.7% Federal National Mortgage Association, Various 1.6% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B427" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000050280 | |
| Shareholder Report [Line Items] | |
| Fund Name | EMERGING MARKETS EQUITY PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Emerging Markets Equity Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B435"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B436" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Emerging Markets Equity Portfolio $46 0.90% |
| Expenses Paid, Amount | $ 46 |
| Expense Ratio, Percent | 0.90% |
| AssetsNet | $ 1,057,373,000 |
| Holdings Count | Holding | 68 |
| InvestmentCompanyPortfolioTurnover | 18% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $1,057,373 # of Portfolio Holdings (Derivatives not included as applicable) 68 Portfolio Turnover Rate 18% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 0.1% Health Care 1.5% Real Estate 2.4% Utilities 2.9% Energy 3.4% Materials 4.8% Consumer Staples 5.1% Industrials 8.4% Communication Services 9.1% Consumer Discretionary 11.0% Financials 20.4% Information Technology 30.9% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Taiwan Semiconductor Manufacturing Co., Ltd. 13.3% Samsung Electronics Co., Ltd., Various 6.9% Tencent Holdings, Ltd. 6.9% Alibaba Group Holding, Ltd. 3.4% Power Grid Corp. of India, Ltd. 2.9% HDFC Bank, Ltd. 2.7% MediaTek, Inc. 2.2% Kaspi.KZ Joint Stock Co., ADR 2.1% Southern Copper Corp. 2.1% SBI Life Insurance Co., Ltd. 1.9% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B446" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000074 | |
| Shareholder Report [Line Items] | |
| Fund Name | SMALL CAP GROWTH STOCK PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Small Cap Growth Stock Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B454"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B455" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Small Cap Growth Stock Portfolio $29 0.56% |
| Expenses Paid, Amount | $ 29 |
| Expense Ratio, Percent | 0.56% |
| AssetsNet | $ 708,949,000 |
| Holdings Count | Holding | 152 |
| InvestmentCompanyPortfolioTurnover | 31% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $708,949 # of Portfolio Holdings (Derivatives not included as applicable) 152 Portfolio Turnover Rate 31% |
| Holdings [Text Block] | Sector Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 0.9% Communication Services 0.6% Investment Companies 1.0% Real Estate 2.1% Consumer Staples 3.5% Energy 3.8% Materials 4.5% Financials 6.2% Consumer Discretionary 12.2% Industrials 19.8% Information Technology 21.1% Health Care 24.3% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) FTAI Aviation, Ltd. 2.2% Fabrinet 1.7% Ensign Group, Inc. 1.6% Verra Mobility Corp. 1.5% Applied Industrial Technologies, Inc. 1.4% SPX Technologies, Inc. 1.3% Cabot Corp. 1.3% Fluor Corp. 1.3% Haemonetics Corp. 1.2% Chart Industries, Inc. 1.2% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B465" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000080 | |
| Shareholder Report [Line Items] | |
| Fund Name | BALANCED PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Balanced Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B473"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B474" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Balanced Portfolio $4 0.08% |
| Expenses Paid, Amount | $ 4 |
| Expense Ratio, Percent | 0.08% |
| AssetsNet | $ 1,938,320,000 |
| Holdings Count | Holding | 24 |
| InvestmentCompanyPortfolioTurnover | 22% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $1,938,320 # of Portfolio Holdings (Derivatives not included as applicable) 24 Portfolio Turnover Rate 22% |
| Holdings [Text Block] | Asset Type Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 2.9% Commodities 0.9% Foreign Equity 14.0% Domestic Equity 29.2% Fixed Income 53.0% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Northwestern Mutual Series Fund, Inc., Select Bond Portfolio 28.3% iShares Core U.S. Aggregate Bond ETF 11.0% Northwestern Mutual Series Fund, Inc., Multi-Sector Bond Portfolio 7.6% iShares Core S&P 500 ETF 7.1% SPDR Portfolio Long Term Treasury ETF 4.9% Northwestern Mutual Series Fund, Inc., International Growth Portfolio 3.9% Northwestern Mutual Series Fund, Inc., Emerging Markets Equity Portfolio 3.8% Northwestern Mutual Series Fund, Inc., International Equity Portfolio 3.7% Northwestern Mutual Series Fund, Inc., Large Cap Blend Portfolio 2.8% Northwestern Mutual Series Fund, Inc., Focused Appreciation Portfolio 2.8% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B484" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000079 | |
| Shareholder Report [Line Items] | |
| Fund Name | ASSET ALLOCATION PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Asset Allocation Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B492"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B493" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Asset Allocation Portfolio $6 0.12% |
| Expenses Paid, Amount | $ 6 |
| Expense Ratio, Percent | 0.12% |
| AssetsNet | $ 274,433,000 |
| Holdings Count | Holding | 24 |
| InvestmentCompanyPortfolioTurnover | 18% |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $274,433 # of Portfolio Holdings (Derivatives not included as applicable) 24 Portfolio Turnover Rate 18% |
| Holdings [Text Block] | Asset Type Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets 3.2% Commodities 1.0% Foreign Equity 19.8% Fixed Income 33.8% Domestic Equity 42.2% |
| Largest Holdings [Text Block] | Top Ten Holdings (% of net assets) Northwestern Mutual Series Fund, Inc., Select Bond Portfolio 16.5% iShares Core S&P 500 ETF 12.3% iShares Core U.S. Aggregate Bond ETF 9.2% Northwestern Mutual Series Fund, Inc., International Growth Portfolio 5.6% Northwestern Mutual Series Fund, Inc., International Equity Portfolio 5.4% Northwestern Mutual Series Fund, Inc., Multi-Sector Bond Portfolio 5.1% Northwestern Mutual Series Fund, Inc., Large Cap Blend Portfolio 4.7% Northwestern Mutual Series Fund, Inc., Focused Appreciation Portfolio 4.7% Northwestern Mutual Series Fund, Inc., Domestic Equity Portfolio 4.6% iShares Core MSCI EAFE ETF 4.5% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B503" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| C000000083 | |
| Shareholder Report [Line Items] | |
| Fund Name | GOVERNMENT MONEY MARKET PORTFOLIO |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Government Money Market Portfolio Fund for the period of 1/1/2024 to 6/30/2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.nmseriesfund.com vavldocrequest northwesternmutual.com |
| Additional Information Phone Number | 1-888-455-2232 |
| Additional Information Email | vavldocrequest@northwesternmutual.com</span>" id="sjs-B511"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">vavldocrequest@northwesternmutual.com</span> |
| Additional Information Website | www.nmseriesfund.com</span> " id="sjs-B512" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
| Expenses [Text Block] | What were the Fund's costs for the past six months? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Government Money Market Portfolio $17 0.33% |
| Expenses Paid, Amount | $ 17 |
| Expense Ratio, Percent | 0.33% |
| AssetsNet | $ 521,330,000 |
| Holdings Count | Holding | 101 |
| Additional Fund Statistics [Text Block] | Fund Statistics Total Net Assets (000's) $521,330 # of Portfolio Holdings (Derivatives not included as applicable) 101 |
| Holdings [Text Block] | Asset Type Weightings (% of net assets) Value Value Short-Term Investments & Other Net Assets - Repurchase Agreements 43.7% US Government & Agencies 56.4% |
| Updated Prospectus Email Address | www.nmseriesfund.com</span> " id="sjs-B520" xml:space="preserve"><span style="box-sizing: border-box; color: rgb(74, 74, 74); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.nmseriesfund.com</span> |
