| Form N-CSR Cover | 12 Months Ended |
| Dec. 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Vanguard Variable Insurance Funds |
| Entity Central Index Key | 0000857490 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Dec. 31, 2024 |
| Shareholder Report | 12 Months Ended |
| Dec. 31, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Vanguard Variable Insurance Funds |
| Entity Central Index Key | 0000857490 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Dec. 31, 2024 |
| C000012148 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Real Estate Index Portfolio |
| Class Name | Real Estate Index Portfolio |
| No Trading Symbol Flag | true |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Real Estate Index Portfolio (the "Fund") for the period of January 1, 2024 |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature. You can also request this information by contacting us at 800-662-7447. |
| Additional Information Phone Number | 800-662-7447 |
| Additional Information Website | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Share Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Vanguard Variable Insurance Funds - $ 0.26 % |
| Expenses Paid, Amount | $ 27 |
| Expense Ratio, Percent | 0.26% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended December 31, 2024, the Fund performed roughly in line with its benchmark. U.S. economic growth hovered around 3% on a year-over-year basis for much of the period, and consumer price inflation trended lower, falling below 3% in July. The Federal Reserve began cutting short-term interest rates in September, which boosted stock returns, as did the prospect of tax cuts and deregulation under the incoming administration. But sticky inflation and solid growth reduced expectations for further rate cuts, which weighed on bond prices and muddied the picture for future mortgage rates. It was a volatile year for real estate, and sectors posted wildly disparate returns. REITs in health care, data centers, retail, and multifamily residences were among those that posted strong double-digit gains, while REITs for industrials and telecom towers, among others, saw double-digit declines. Note that the Fund’s returns differ from those of variable annuity products that invest in the Fund. Annuity returns take insurance-related fees and expenses into account, and the Fund’s returns do not. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. |
| Line Graph [Table Text Block] | How did the Fund perform over the past 10 years? Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. Nor do the returns reflect fees and expenses associated with the annuity or life insurance program through which a shareholder invests. If these fees and expenses were included, the Fund's returns would be lower. Cumulative Performance: December 31, 2014, Through December 31, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Years 10 Years Vanguard Variable Insurance Funds - 4.74% 2.84% 4.99% Real Estate Spliced Index 5.05% 3.12% 5.25% Dow Jones U.S. Total Stock Market Float Adjusted Index 23.88% 13.78% 12.48% |
| No Deduction of Taxes [Text Block] | The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. |
| Updated Performance Information Location [Text Block] | Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. |
| Net Assets | $ 1,103,000,000 |
| Holdings Count | Holding | 158 |
| Advisory Fees Paid, Amount | $ 18,000 |
| Investment Company Portfolio Turnover | 11% |
| Additional Fund Statistics [Text Block] | Fund Statistics Fund Net Assets $ Number of Portfolio Holdings 158 Portfolio Turnover Rate 11 % Total Investment Advisory Fees $ |
| Holdings [Text Block] | This table reflects the Fund’s investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets Data Center REITs 10.2 % Health Care REITs 11.8 % Industrial REITs 10.2 % Multi-Family Residential REITs 8.9 % Office REITs 3.4 % Other Specialized REITs 6.7 % Real Estate Services 7.5 % Retail REITs 13.8 % Self-Storage REITs 6.3 % Single-Family Residential REITs 4.1 % Telecom Tower REITs 10.2 % Other Assets and Liabilities—Net 6.9 % |
| C000012152 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Total Stock Market Index Portfolio |
| Class Name | Total Stock Market Index Portfolio |
| No Trading Symbol Flag | true |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Total Stock Market Index Portfolio (the "Fund") for the period of January 1, 2024 |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature. You can also request this information by contacting us at 800-662-7447. |
| Material Fund Change Notice [Text Block] | The report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 800-662-7447 |
| Additional Information Website | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Share Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Vanguard Variable Insurance Funds - $ 0.13 % |
| Expenses Paid, Amount | $ 15 |
| Expense Ratio, Percent | 0.13% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended December 31, 2024, the Fund performed roughly in line with its benchmark index. U.S. economic growth hovered around 3% on a year-by-year basis for much of the period, and consumer price inflation trended lower, falling below 3% in July. The Federal Reserve began cutting short-term interest rates in September, which boosted stock returns, as did the prospect of tax cuts and deregulation under the incoming administration. Each of the benchmark’s 11 industry sectors recorded positive returns for the 12 months. Information technology, the index’s largest sector by weight, posted extremely strong results and was by far the greatest contributor to return. Financials and communication services were also among the top contributors. For the decade ended December 31, the Fund performed roughly in line with its benchmark, which returned about 12.50%, annualized. Note that the Fund’s returns differ from those of variable annuity products that invest in the Fund. Annuity returns take insurance-related fees and expenses into account, and the Fund’s returns do not. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. |
| Line Graph [Table Text Block] | How did the Fund perform over the past 10 years? Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. Nor do the returns reflect fees and expenses associated with the annuity or life insurance program through which a shareholder invests. If these fees and expenses were included, the Fund's returns would be lower. Cumulative Performance: December 31, 2014, Through December 31, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Years 10 Years Vanguard Variable Insurance Funds - 23.71% 13.67% 12.37% S&P Total Market Index 23.88% 13.78% 12.48% Dow Jones U.S. Total Stock Market Float Adjusted Index 23.88% 13.78% 12.48% |
| No Deduction of Taxes [Text Block] | The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. |
| Updated Performance Information Location [Text Block] | Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. |
| Net Assets | $ 5,423,000,000 |
| Holdings Count | Holding | 3 |
| Advisory Fees Paid, Amount | $ 0 |
| Investment Company Portfolio Turnover | 6% |
| Additional Fund Statistics [Text Block] | Fund Statistics Fund Net Assets $ Number of Portfolio Holdings 3 Portfolio Turnover Rate 6 % Total Investment Advisory Fees $ |
| Holdings [Text Block] | This table reflects the Fund’s investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets Vanguard Variable Insurance Funds—Equity Index Portfolio 87.2 % Vanguard Extended Market Index Fund Admiral Shares 12.8 % Other Assets and Liabilities—Net 0.0 % |
| Material Fund Change [Text Block] | How has the Fund changed? The Fund's principal investment strategy disclosure was modified to add that the Fund may become nondiversified under the Investment Company Act of 1940 solely as a result of an index rebalance or market movement. The Fund added nondiversification risk and sector risk as principal risks. This is a summary of certain changes to the Fund since December 31, 2023. For more complete information, you may review the Fund’s next prospectus, which we expect to be available by April 30, 2025, at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature or upon request at 800-662-7447. |
| Material Fund Change Strategies [Text Block] | The Fund's principal investment strategy disclosure was modified to add that the Fund may become nondiversified under the Investment Company Act of 1940 solely as a result of an index rebalance or market movement. |
| Material Fund Change Risks Change [Text Block] | The Fund added nondiversification risk and sector risk as principal risks. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since December 31, 2023. For more complete information, you may review the Fund’s next prospectus, which we expect to be available by April 30, 2025, at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature or upon request at 800-662-7447. |
| Updated Prospectus Phone Number | 800-662-7447 |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012156 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Equity Index Portfolio |
| Class Name | Equity Index Portfolio |
| No Trading Symbol Flag | true |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Equity Index Portfolio (the "Fund") for the period of January 1, 2024 |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature. You can also request this information by contacting us at 800-662-7447. |
| Material Fund Change Notice [Text Block] | The report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 800-662-7447 |
| Additional Information Website | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Share Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Vanguard Variable Insurance Funds - $ 0.14 % |
| Expenses Paid, Amount | $ 16 |
| Expense Ratio, Percent | 0.14% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended December 31, 2024, the Fund performed in line with its benchmark, the Standard & Poor’s 500 Index. U.S. economic growth hovered around 3% on a year-by-year basis for much of the period, and consumer price inflation trended lower, falling below 3% in July. The Federal Reserve began cutting short-term interest rates in September, which boosted stock returns, as did the prospect of tax cuts and deregulation under the incoming administration. Ten of the benchmark’s 11 industry sectors recorded positive results for the 12 months. Information technology, the index’s largest sector by weight, posted extremely strong results and was by far the largest contributor to return. Financial and communication services stocks were also among the top contributors. For the decade ended December 31, 2024, the Fund performed in line with its benchmark, which returned a bit more than 13%, annualized. Note that the Fund’s returns differ from those of variable annuity products that invest in the Fund. Annuity returns take insurance-related fees and expenses into account, and the Fund’s returns do not. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. |
| Line Graph [Table Text Block] | How did the Fund perform over the past 10 years? Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. Nor do the returns reflect fees and expenses associated with the annuity or life insurance program through which a shareholder invests. If these fees and expenses were included, the Fund's returns would be lower. Cumulative Performance: December 31, 2014, Through December 31, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Years 10 Years Vanguard Variable Insurance Funds - 24.84% 14.36% 12.95% S&P 500 Index 25.02% 14.53% 13.10% Dow Jones U.S. Total Stock Market Float Adjusted Index 23.88% 13.78% 12.48% |
| No Deduction of Taxes [Text Block] | The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. |
| Updated Performance Information Location [Text Block] | Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. |
| Net Assets | $ 11,479,000,000 |
| Holdings Count | Holding | 505 |
| Advisory Fees Paid, Amount | $ 253,000 |
| Investment Company Portfolio Turnover | 4% |
| Additional Fund Statistics [Text Block] | Fund Statistics Fund Net Assets $ Number of Portfolio Holdings 505 Portfolio Turnover Rate 4 % Total Investment Advisory Fees $ |
| Holdings [Text Block] | This table reflects the Fund’s investments, including short-term investments, derivatives and other assets and liabilities. Portfolio Composition % of Net Assets Communication Services 9.4 % Consumer Discretionary 11.2 % Consumer Staples 5.5 % Energy 3.2 % Financials 13.6 % Health Care 10.1 % Industrials 8.1 % Information Technology 32.5 % Materials 1.9 % Real Estate 2.1 % Utilities 2.3 % Other Assets and Liabilities—Net 0.1 % |
| Material Fund Change [Text Block] | How has the Fund changed? The Fund's principal investment strategy disclosure was modified to add that the Fund may become nondiversified under the Investment Company Act of 1940 solely as a result of an index rebalance or market movement. The Fund added nondiversification risk and sector risk as principal risks. This is a summary of certain changes to the Fund since December 31, 2023. For more complete information, you may review the Fund’s next prospectus, which we expect to be available by April 30, 2025, at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature or upon request at 800-662-7447. |
| Material Fund Change Strategies [Text Block] | The Fund's principal investment strategy disclosure was modified to add that the Fund may become nondiversified under the Investment Company Act of 1940 solely as a result of an index rebalance or market movement. |
| Material Fund Change Risks Change [Text Block] | The Fund added nondiversification risk and sector risk as principal risks. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since December 31, 2023. For more complete information, you may review the Fund’s next prospectus, which we expect to be available by April 30, 2025, at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature or upon request at 800-662-7447. |
| Updated Prospectus Phone Number | 800-662-7447 |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012160 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Mid-Cap Index Portfolio |
| Class Name | Mid-Cap Index Portfolio |
| No Trading Symbol Flag | true |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Mid-Cap Index Portfolio (the "Fund") for the period of January 1, 2024 |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature. You can also request this information by contacting us at 800-662-7447. |
| Additional Information Phone Number | 800-662-7447 |
| Additional Information Website | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Share Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Vanguard Variable Insurance Funds - $ 0.17 % |
| Expenses Paid, Amount | $ 18 |
| Expense Ratio, Percent | 0.17% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended December 31, 2024, the Fund performed roughly in line with its benchmark, the CRSP US Mid Cap Index. U.S. economic growth hovered around 3% on a year-over-year basis for much of the period, and consumer price inflation trended lower, falling below 3% in July. The Federal Reserve began cutting short-term interest rates in September, which boosted stock returns, as did the prospect of tax cuts and deregulation under the incoming administration. Nine of the benchmark’s 11 industry sectors posted positive returns. Industrials and financials contributed most to the benchmark’s total return. Other notable contributors included technology, utility, and consumer discretionary companies. Health care and basic materials stocks detracted. Note that the Fund’s returns differ from those of variable annuity products that invest in the Fund. Annuity returns take insurance-related fees and expenses into account, and the Fund’s returns do not. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. |
| Line Graph [Table Text Block] | How did the Fund perform over the past 10 years? Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. Nor do the returns reflect fees and expenses associated with the annuity or life insurance program through which a shareholder invests. If these fees and expenses were included, the Fund's returns would be lower. Cumulative Performance: December 31, 2014, Through December 31, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Years 10 Years Vanguard Variable Insurance Funds - 15.08% 9.70% 9.41% CRSP US Mid Cap Index 15.25% 9.86% 9.57% Dow Jones U.S. Total Stock Market Float Adjusted Index 23.88% 13.78% 12.48% |
| No Deduction of Taxes [Text Block] | The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. |
| Updated Performance Information Location [Text Block] | Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. |
| Net Assets | $ 2,891,000,000 |
| Holdings Count | Holding | 319 |
| Advisory Fees Paid, Amount | $ 46,000 |
| Investment Company Portfolio Turnover | 21% |
| Additional Fund Statistics [Text Block] | Fund Statistics Fund Net Assets $ Number of Portfolio Holdings 319 Portfolio Turnover Rate 21 % Total Investment Advisory Fees $ |
| Holdings [Text Block] | This table reflects the Fund’s investments, including short-term investments, derivatives and other assets and liabilities. Portfolio Composition % of Net Assets Basic Materials 2.6 % Consumer Discretionary 13.1 % Consumer Staples 5.9 % Energy 5.5 % Financials 13.5 % Health Care 8.6 % Industrials 19.9 % Real Estate 7.7 % Technology 13.9 % Telecommunications 1.0 % Utilities 8.2 % Other Assets and Liabilities—Net 0.1 % |
| C000102905 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Conservative Allocation Portfolio |
| Class Name | Conservative Allocation Portfolio |
| No Trading Symbol Flag | true |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Conservative Allocation Portfolio (the "Fund") for the period of January 1, 2024 |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature. You can also request this information by contacting us at 800-662-7447. |
| Material Fund Change Notice [Text Block] | The report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 800-662-7447 |
| Additional Information Website | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Share Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Vanguard Variable Insurance Funds - $ 0.13 % |
| Expenses Paid, Amount | $ 13 |
| Expense Ratio, Percent | 0.13% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended December 31, 2024, the Fund performed roughly in line with its benchmark. U.S. economic growth hovered around 3% on a year-over-year basis for much of the period, and consumer price inflation trended lower, falling below 3% in July. The Federal Reserve began cutting short-term interest rates in September, boosting stock returns, but sticky inflation and solid growth reduced expectations for further rate cuts, which weighed on bond prices. The Fund targets an asset allocation of approximately 40% stocks and 60% bonds by investing in a range of underlying Vanguard funds. The Variable Insurance Funds Equity Index Portfolio, which returned 24.84%, helped performance the most; Extended Market Index Fund Admiral Shares returned 16.91%. Total International Stock Index Fund Admiral Shares returned 5.14%, Total International Bond Index Fund Admiral Shares 3.67%, and the Note that the Fund’s returns differ from those of variable annuity products that invest in the Fund. Annuity returns take insurance-related fees and expenses into account, and the Fund’s returns do not. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. |
| Line Graph [Table Text Block] | How did the Fund perform over the past 10 years? Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. Nor do the returns reflect fees and expenses associated with the annuity or life insurance program through which a shareholder invests. If these fees and expenses were included, the Fund's returns would be lower. Cumulative Performance: December 31, 2014, Through December 31, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Years 10 Years Vanguard Variable Insurance Funds - 7.49% 4.04% 4.90% Conservative Allocation Composite Index 7.73% 4.35% 5.13% Dow Jones U.S. Total Stock Market Float Adjusted Index 23.88% 13.78% 12.48% Bloomberg U.S. Aggregate Float Adjusted Index 1.33% -0.27% 1.39% |
| No Deduction of Taxes [Text Block] | The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. |
| Updated Performance Information Location [Text Block] | Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. |
| Net Assets | $ 469,000,000 |
| Holdings Count | Holding | 6 |
| Advisory Fees Paid, Amount | $ 0 |
| Investment Company Portfolio Turnover | 9% |
| Additional Fund Statistics [Text Block] | Fund Statistics Fund Net Assets $ Number of Portfolio Holdings 6 Portfolio Turnover Rate 9 % Total Investment Advisory Fees $ |
| Holdings [Text Block] | This table reflects the Fund’s investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets Vanguard Variable Insurance Funds—Total Bond Market Index Portfolio 42.2 % Vanguard Variable Insurance Funds—Equity Index Portfolio 20.8 % Vanguard Total International Bond Index Fund Admiral Shares 18.2 % Vanguard Total International Stock Index Fund Admiral Shares 15.4 % Vanguard Extended Market Index Fund Admiral Shares 3.4 % Other Assets and Liabilities—Net 0.0 % |
| Material Fund Change [Text Block] | How has the Fund changed? Subsequent to the Fund's fiscal year end, its expense ratio was reduced. This is a summary of certain changes to the Fund since December 31, 2023. For more complete information, you may review the Fund’s next prospectus, which we expect to be available by April 30, 2025, at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature or upon request at 800-662-7447. |
| Material Fund Change Expenses [Text Block] | Subsequent to the Fund's fiscal year end, its expense ratio was reduced. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since December 31, 2023. For more complete information, you may review the Fund’s next prospectus, which we expect to be available by April 30, 2025, at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature or upon request at 800-662-7447. |
| Updated Prospectus Phone Number | 800-662-7447 |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000102906 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Moderate Allocation Portfolio |
| Class Name | Moderate Allocation Portfolio |
| No Trading Symbol Flag | true |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Moderate Allocation Portfolio (the "Fund") for the period of January 1, 2024 |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature. You can also request this information by contacting us at 800-662-7447. |
| Material Fund Change Notice [Text Block] | The report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 800-662-7447 |
| Additional Information Website | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Share Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Vanguard Variable Insurance Funds - $ 0.13 % |
| Expenses Paid, Amount | $ 14 |
| Expense Ratio, Percent | 0.13% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended December 31, 2024, the Fund performed roughly in line with its benchmark. U.S. economic growth hovered around 3% on a year-over-year basis for much of the period, and consumer price inflation trended lower, falling below 3% in July. The Federal Reserve began cutting short-term interest rates in September, boosting stock returns, but sticky inflation and solid growth reduced expectations for further rate cuts, which weighed on bond prices. The Fund targets an asset allocation of approximately 60% stocks and 40% bonds by investing in a range of underlying Vanguard funds. The Variable Insurance Funds Equity Index Portfolio, which returned 24.84%, helped performance the most; Extended Market Index Fund Admiral Shares returned 16.91%. Total International Stock Index Fund Admiral Shares returned 5.14%, Total International Bond Index Fund Admiral Shares 3.67%, and the Variable Insurance Funds Total Bond Market Index Portfolio 1.24%. Note that the Fund’s returns differ from those of variable annuity products that invest in the Fund. Annuity returns take insurance-related fees and expenses into account, and the Fund’s returns do not. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. |
| Line Graph [Table Text Block] | How did the Fund perform over the past 10 years? Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. Nor do the returns reflect fees and expenses associated with the annuity or life insurance program through which a shareholder invests. If these fees and expenses were included, the Fund's returns would be lower. Cumulative Performance: December 31, 2014, Through December 31, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Years 10 Years Vanguard Variable Insurance Funds - 10.32% 6.06% 6.52% Moderate Allocation Composite Index 10.60% 6.46% 6.80% Dow Jones U.S. Total Stock Market Float Adjusted Index 23.88% 13.78% 12.48% Bloomberg U.S. Aggregate Float Adjusted Index 1.33% -0.27% 1.39% |
| No Deduction of Taxes [Text Block] | The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. |
| Updated Performance Information Location [Text Block] | Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. |
| Net Assets | $ 678,000,000 |
| Holdings Count | Holding | 6 |
| Advisory Fees Paid, Amount | $ 0 |
| Investment Company Portfolio Turnover | 10% |
| Additional Fund Statistics [Text Block] | Fund Statistics Fund Net Assets $ Number of Portfolio Holdings 6 Portfolio Turnover Rate 10 % Total Investment Advisory Fees $ |
| Holdings [Text Block] | This table reflects the Fund’s investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets Vanguard Variable Insurance Funds—Equity Index Portfolio 32.0 % Vanguard Variable Insurance Funds—Total Bond Market Index Portfolio 28.3 % Vanguard Total International Stock Index Fund Admiral Shares 22.7 % Vanguard Total International Bond Index Fund Admiral Shares 12.2 % Vanguard Extended Market Index Fund Admiral Shares 4.9 % Other Assets and Liabilities—Net (0.1 ) % |
| Material Fund Change [Text Block] | How has the Fund changed? Subsequent to the Fund's fiscal year end, its expense ratio was reduced. This is a summary of certain changes to the Fund since December 31, 2023. For more complete information, you may review the Fund’s next prospectus, which we expect to be available by April 30, 2025, at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature or upon request at 800-662-7447. |
| Material Fund Change Expenses [Text Block] | Subsequent to the Fund's fiscal year end, its expense ratio was reduced. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since December 31, 2023. For more complete information, you may review the Fund’s next prospectus, which we expect to be available by April 30, 2025, at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature or upon request at 800-662-7447. |
| Updated Prospectus Phone Number | 800-662-7447 |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000192542 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Global Bond Index Portfolio |
| Class Name | Global Bond Index Portfolio |
| No Trading Symbol Flag | true |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Global Bond Index Portfolio (the "Fund") for the period of January 1, 2024 |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature. You can also request this information by contacting us at 800-662-7447. |
| Additional Information Phone Number | 800-662-7447 |
| Additional Information Website | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Share Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Vanguard Variable Insurance Funds - $ 0.13 % |
| Expenses Paid, Amount | $ 13 |
| Expense Ratio, Percent | 0.13% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended December 31, 2024, the Fund performed in line with its expense-free benchmark, the Global Bond Composite Index. Overall, the global economy continued to expand, and consumer price inflation trended lower. That supportive backdrop set the stage for the European Central Bank, the Bank of England, and the U.S. Federal Reserve to begin cutting short-term interest rates this past summer, although longer-term rates moved higher in December in a number of markets. Returns were positive for most countries. Generally, bonds with shorter maturities returned more than those with longer maturities. Outside the U.S., lower-rated investment-grade bonds tended to outperform higher-rated ones. Inside the U.S., the highest- and lowest-rated investment-grade bonds outperformed those in the middle. Note that the Fund’s returns differ from those of variable annuity products that invest in the Fund. Annuity returns take insurance-related fees and expenses into account, and the Fund’s returns do not. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. |
| Line Graph [Table Text Block] | How did the Fund perform since inception? Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. Nor do the returns reflect fees and expenses associated with the annuity or life insurance program through which a shareholder invests. If these fees and expenses were included, the Fund's returns would be lower. Cumulative Performance: September 7, 2017, Through December 31, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Years Since Inception Vanguard Variable Insurance Funds - 2.03% -0.23% 1.04 % Global Bond Composite Index 2.07% -0.11% 1.16% Bloomberg Global Aggregate Float Adjusted Index * -1.09% -1.54% -0.42% Bloomberg Global Aggregate Float Adjusted Index Hedged 3.54% 0.52% 1.73% * The Fund's broad-based benchmark is different from the one used for the immediately preceding fiscal year to reflect new regulatory requirements. The Bloomberg Global Aggregate Float Adjusted Index is considered broadly representative of the overall securities market applicable to the Fund. |
| Performance Inception Date | Sep. 07, 2017 |
| No Deduction of Taxes [Text Block] | The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. |
| Updated Performance Information Location [Text Block] | Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. |
| Net Assets | $ 488,000,000 |
| Holdings Count | Holding | 3 |
| Advisory Fees Paid, Amount | $ 0 |
| Investment Company Portfolio Turnover | 10% |
| Additional Fund Statistics [Text Block] | Fund Statistics Fund Net Assets $ Number of Portfolio Holdings 3 Portfolio Turnover Rate 10 % Total Investment Advisory Fees $ |
| Holdings [Text Block] | This table reflects the Fund’s investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets Vanguard Variable Insurance Funds—Total Bond Market Index Portfolio 70.0 % Vanguard Total International Bond Index Fund Admiral Shares 30.0 % Other Assets and Liabilities—Net 0.0 % |
| C000192543 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Total International Stock Market Index Portfolio |
| Class Name | Total International Stock Market Index Portfolio |
| No Trading Symbol Flag | true |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Total International Stock Market Index Portfolio (the "Fund") for the period of January 1, 2024 |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature. You can also request this information by contacting us at 800-662-7447. |
| Material Fund Change Notice [Text Block] | The report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 800-662-7447 |
| Additional Information Website | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Share Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Vanguard Variable Insurance Funds - $ 0.11 % |
| Expenses Paid, Amount | $ 11 |
| Expense Ratio, Percent | 0.11% |
| Factors Affecting Performance [Text Block] | How did the Fund perform during the reporting period? For the 12 months ended December 31, 2024, the Fund underperformed its benchmark, the FTSE Global All Cap ex US Index. This was largely because of differences in the price of securities used by the Fund to calculate its net asset value and the published prices for the same securities. This practice is known as fair-value pricing. Overall, the global economy continued to expand, and consumer price inflation trended lower. That supportive backdrop set the stage for the European Central Bank, the Bank of England, and the U.S. Federal Reserve to begin cutting short-term interest rates this past summer, although longer-term rates moved higher in December in a number of markets. Among economic sectors, financial and information technology stocks contributed most to the benchmark’s return. Detractors included basic materials and consumer staples stocks. Note that the Fund’s returns differ from those of variable annuity products that invest in the Fund. Annuity returns take insurance-related fees and expenses into account, and the Fund’s returns do not. |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. |
| Line Graph [Table Text Block] | How did the Fund perform since inception? Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. Nor do the returns reflect fees and expenses associated with the annuity or life insurance program through which a shareholder invests. If these fees and expenses were included, the Fund's returns would be lower. Cumulative Performance: September 7, 2017, Through December 31, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Years Since Inception Vanguard Variable Insurance Funds - 5.06% 4.23% 4.19 % FTSE Global All Cap ex US Index 5.53% 4.42% 4.43% MSCI All Country World Index ex USA Net 5.53% 4.10% 4.21% |
| Performance Inception Date | Sep. 07, 2017 |
| No Deduction of Taxes [Text Block] | The graph and returns shown do not reflect taxes that a shareholder would pay on fund distributions or on the sale of fund shares. |
| Updated Performance Information Location [Text Block] | Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447. |
| Net Assets | $ 1,561,000,000 |
| Holdings Count | Holding | 8 |
| Advisory Fees Paid, Amount | $ 0 |
| Investment Company Portfolio Turnover | 16% |
| Additional Fund Statistics [Text Block] | Fund Statistics Fund Net Assets $ Number of Portfolio Holdings 8 Portfolio Turnover Rate 16 % Total Investment Advisory Fees $ |
| Holdings [Text Block] | This table reflects the Fund’s investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets Vanguard FTSE All-World ex-US Index Fund Admiral Shares 28.0 % Vanguard Developed Markets Index Fund Admiral Shares 28.0 % Vanguard Emerging Markets Stock Index Fund Admiral Shares 19.4 % Vanguard European Stock Index Fund Admiral Shares 11.5 % Vanguard Pacific Stock Index Fund Admiral Shares 7.8 % Vanguard FTSE All-World ex-US Small-Cap Index Fund Admiral Shares 3.2 % Vanguard FTSE Canada All Cap Index ETF 2.1 % Other Assets and Liabilities—Net 0.0 % |
| Material Fund Change [Text Block] | How has the Fund changed? Subsequent to the Fund's fiscal year end, its expense ratio was reduced. This is a summary of certain changes to the Fund since December 31, 2023. For more complete information, you may review the Fund’s next prospectus, which we expect to be available by April 30, 2025, at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature or upon request at 800-662-7447. |
| Material Fund Change Expenses [Text Block] | Subsequent to the Fund's fiscal year end, its expense ratio was reduced. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since December 31, 2023. For more complete information, you may review the Fund’s next prospectus, which we expect to be available by April 30, 2025, at https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature or upon request at 800-662-7447. |
| Updated Prospectus Phone Number | 800-662-7447 |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| Shareholder Report, Line Graph (Details) - USD ($) | 12 Months Ended | 60 Months Ended | 88 Months Ended | 120 Months Ended | ||||||||||||
| Dec. 31, 2024 | Dec. 31, 2024 | Dec. 31, 2024 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Sep. 07, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | ||
| C000012148 [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Vanguard Variable Insurance Funds - Real Estate Index Portfolio | |||||||||||||||
| Account Value | $ 16,276 | $ 16,276 | $ 16,276 | $ 16,276 | $ 15,539 | $ 13,911 | $ 18,875 | $ 13,462 | $ 14,149 | $ 10,984 | $ 11,606 | $ 11,076 | $ 10,222 | $ 10,000 | ||
| Average Annual Return, Percent | 4.74% | 2.84% | 4.99% | |||||||||||||
| C000012152 [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Vanguard Variable Insurance Funds -Total Stock Market Index Portfolio | |||||||||||||||
| Account Value | $ 32,098 | $ 32,098 | 32,098 | $ 32,098 | 25,945 | 20,600 | 25,619 | 20,391 | 16,914 | 12,936 | 13,666 | 11,297 | 10,037 | 10,000 | ||
| Average Annual Return, Percent | 23.71% | 13.67% | 12.37% | |||||||||||||
| C000012156 [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Vanguard Variable Insurance Funds -Equity Index Portfolio | |||||||||||||||
| Account Value | $ 33,786 | $ 33,786 | 33,786 | $ 33,786 | 27,063 | 21,459 | 26,243 | 20,415 | 17,271 | 13,154 | 13,775 | 11,323 | 10,127 | 10,000 | ||
| Average Annual Return, Percent | 24.84% | 14.36% | 12.95% | |||||||||||||
| C000012160 [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Vanguard Variable Insurance Funds - Mid-Cap Index Portfolio | |||||||||||||||
| Account Value | $ 24,587 | $ 24,587 | 24,587 | $ 24,587 | 21,366 | 18,446 | 22,722 | 18,272 | 15,475 | 11,825 | 13,042 | 10,952 | 9,857 | 10,000 | ||
| Average Annual Return, Percent | 15.08% | 9.70% | 9.41% | |||||||||||||
| C000102905 [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Vanguard Variable Insurance Funds - Conservative Allocation Portfolio | |||||||||||||||
| Account Value | $ 16,133 | $ 16,133 | 16,133 | $ 16,133 | 15,009 | 13,340 | 15,675 | 14,789 | 13,237 | 11,428 | 11,779 | 10,623 | 10,020 | 10,000 | ||
| Average Annual Return, Percent | 7.49% | 4.04% | 4.90% | |||||||||||||
| C000102906 [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Vanguard Variable Insurance Funds - Moderate Allocation Portfolio | |||||||||||||||
| Account Value | $ 18,798 | $ 18,798 | 18,798 | $ 18,798 | 17,039 | 14,746 | 17,540 | 15,935 | 14,006 | 11,718 | 12,326 | 10,737 | 9,984 | 10,000 | ||
| Average Annual Return, Percent | 10.32% | 6.06% | 6.52% | |||||||||||||
| C000192542 [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Vanguard Variable Insurance Funds - Global Bond Index Portfolio | |||||||||||||||
| Account Value | $ 10,785 | $ 10,785 | $ 10,785 | $ 10,785 | 10,570 | 9,923 | 11,423 | 11,637 | 10,909 | 10,063 | 9,985 | $ 10,000 | ||||
| Average Annual Return, Percent | 2.03% | (0.23%) | 1.04% | |||||||||||||
| C000192543 [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Vanguard Variable Insurance Funds - Total International Stock Market Index Portfolio | |||||||||||||||
| Account Value | $ 13,501 | $ 13,501 | $ 13,501 | 13,501 | 12,851 | 11,122 | 13,243 | 12,202 | 10,975 | 9,029 | 10,575 | 10,000 | ||||
| Average Annual Return, Percent | 5.06% | 4.23% | 4.19% | |||||||||||||
| Dow Jones U S Total Stock Market Float Adjusted Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Dow Jones U.S. Total Stock Market Float Adjusted Index | |||||||||||||||
| Account Value | $ 32,405 | $ 32,405 | $ 32,405 | $ 32,405 | 26,160 | 20,752 | 25,788 | 20,523 | 16,990 | 12,979 | 13,705 | 11,312 | 10,044 | 10,000 | ||
| Average Annual Return, Percent | 23.88% | 13.78% | 12.48% | |||||||||||||
| Bloomberg U S Aggregate Float Adjusted Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Bloomberg U.S. Aggregate Float Adjusted Index | |||||||||||||||
| Account Value | $ 11,476 | $ 11,476 | 11,476 | $ 11,476 | 11,326 | 10,726 | 12,338 | 12,536 | 11,635 | 10,687 | 10,695 | 10,321 | 10,044 | 10,000 | ||
| Average Annual Return, Percent | 1.33% | (0.27%) | 1.39% | |||||||||||||
| Bloomberg Global Aggregate Float Adjusted Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Bloomberg Global Aggregate Float Adjusted Index | |||||||||||||||
| Account Value | $ 9,700 | $ 9,700 | $ 9,700 | $ 9,700 | 9,807 | 9,209 | 10,987 | 11,495 | 10,482 | 9,779 | 9,935 | 10,000 | ||||
| Average Annual Return, Percent | [1] | (1.09%) | (1.54%) | (0.42%) | ||||||||||||
| Bloomberg Global Aggregate Float Adjusted Index Hedged [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Bloomberg Global Aggregate Float Adjusted Index Hedged | |||||||||||||||
| Account Value | $ 11,336 | $ 11,336 | $ 11,336 | 11,336 | 10,948 | 10,203 | 11,543 | 11,712 | 11,048 | 10,171 | 10,005 | 10,000 | ||||
| Average Annual Return, Percent | 3.54% | 0.52% | 1.73% | |||||||||||||
| MSCI All Country World Index ex USA Net [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | MSCI All Country World Index ex USA Net | |||||||||||||||
| Account Value | $ 13,519 | $ 13,519 | $ 13,519 | 13,519 | 12,810 | 11,080 | 13,191 | 12,233 | 11,056 | 9,099 | 10,604 | 10,000 | ||||
| Average Annual Return, Percent | 5.53% | 4.10% | 4.21% | |||||||||||||
| Real Estate Spliced Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Real Estate Spliced Index | |||||||||||||||
| Account Value | $ 16,677 | $ 16,677 | $ 16,677 | $ 16,677 | 15,875 | 14,180 | 19,192 | 13,654 | 14,306 | 11,087 | 11,698 | 11,134 | 10,252 | 10,000 | ||
| Average Annual Return, Percent | 5.05% | 3.12% | 5.25% | |||||||||||||
| S And P Total Market Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | S&P Total Market Index | |||||||||||||||
| Account Value | $ 32,424 | $ 32,424 | 32,424 | $ 32,424 | 26,175 | 20,764 | 25,803 | 20,534 | 17,000 | 12,987 | 13,713 | 11,318 | 10,047 | 10,000 | ||
| Average Annual Return, Percent | 23.88% | 13.78% | 12.48% | |||||||||||||
| Standard And Poor s 500 S000004400 Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | S&P 500 Index | |||||||||||||||
| Account Value | $ 34,254 | $ 34,254 | 34,254 | $ 34,254 | 27,399 | 21,696 | 26,494 | 20,585 | 17,386 | 13,223 | 13,829 | 11,351 | 10,138 | 10,000 | ||
| Average Annual Return, Percent | 25.02% | 14.53% | 13.10% | |||||||||||||
| CRSP US Mid Cap Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | CRSP US Mid Cap Index | |||||||||||||||
| Account Value | $ 24,951 | $ 24,951 | 24,951 | $ 24,951 | 21,649 | 18,667 | 22,956 | 18,435 | 15,590 | 11,893 | 13,101 | 10,982 | 9,872 | 10,000 | ||
| Average Annual Return, Percent | 15.25% | 9.86% | 9.57% | |||||||||||||
| Conservative Allocation Composite Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Conservative Allocation Composite Index | |||||||||||||||
| Account Value | $ 16,497 | $ 16,497 | 16,497 | $ 16,497 | 15,314 | 13,587 | 15,893 | 14,960 | 13,330 | 11,497 | 11,841 | 10,661 | 10,032 | 10,000 | ||
| Average Annual Return, Percent | 7.73% | 4.35% | 5.13% | |||||||||||||
| Moderate Allocation Composite Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Moderate Allocation Composite Index | |||||||||||||||
| Account Value | $ 19,312 | $ 19,312 | 19,312 | $ 19,312 | 17,461 | 15,077 | 17,834 | 16,160 | 14,122 | 11,799 | 12,401 | $ 10,776 | $ 10,003 | $ 10,000 | ||
| Average Annual Return, Percent | 10.60% | 6.46% | 6.80% | |||||||||||||
| Global Bond Composite Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | Global Bond Composite Index | |||||||||||||||
| Account Value | $ 10,882 | $ 10,882 | $ 10,882 | $ 10,882 | 10,661 | 10,004 | 11,491 | 11,692 | 10,943 | 10,073 | 9,984 | 10,000 | ||||
| Average Annual Return, Percent | 2.07% | (0.11%) | 1.16% | |||||||||||||
| FTSE Global All Cap ex US Index [Member] | ||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||
| Line Graph and Table Measure Name | FTSE Global All Cap ex US Index | |||||||||||||||
| Account Value | $ 13,727 | $ 13,727 | $ 13,727 | $ 13,727 | $ 13,009 | $ 11,234 | $ 13,390 | $ 12,303 | $ 11,059 | $ 9,080 | $ 10,634 | $ 10,000 | ||||
| Average Annual Return, Percent | 5.53% | 4.42% | 4.43% | |||||||||||||
| [1]The Fund's broad-based benchmark is different from the one used for the immediately preceding fiscal year to reflect new regulatory requirements. The Bloomberg Global Aggregate Float Adjusted Index is considered broadly representative of the overall securities market applicable to the Fund. | ||||||||||||||||
| Shareholder Report, Holdings (Details) | Dec. 31, 2024 |
| C000012148 [Member] | Data Center REITs [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.20% |
| C000012148 [Member] | Health Care REITs [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.80% |
| C000012148 [Member] | Industrial REITs [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.20% |
| C000012148 [Member] | Multi Family Residential REITs [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.90% |
| C000012148 [Member] | Office REITs [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.40% |
| C000012148 [Member] | Other Specialized REITs [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.70% |
| C000012148 [Member] | Real Estate Services [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.50% |
| C000012148 [Member] | Retail REITs [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.80% |
| C000012148 [Member] | Self Storage REITs [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.30% |
| C000012148 [Member] | Single Family Residential REITs [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.10% |
| C000012148 [Member] | Telecom Tower REITs [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.20% |
| C000012148 [Member] | Other Assets and Liabilities Net [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.90% |
| C000012152 [Member] | Other Assets and Liabilities Net [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| C000012152 [Member] | Vanguard Variable Insurance Funds Equity Index Portfolio [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 87.20% |
| C000012152 [Member] | Vanguard Extended Market Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.80% |
| C000012156 [Member] | Communications Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.40% |
| C000012156 [Member] | Consumer Discretionary Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.20% |
| C000012156 [Member] | Consumer Staples Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.50% |
| C000012156 [Member] | Energy Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.20% |
| C000012156 [Member] | Financial Services Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.60% |
| C000012156 [Member] | Healthcare Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.10% |
| C000012156 [Member] | Industrial Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.10% |
| C000012156 [Member] | Information Technology Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 32.50% |
| C000012156 [Member] | Materials Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.90% |
| C000012156 [Member] | Real Estate Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.10% |
| C000012156 [Member] | Utilities Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.30% |
| C000012156 [Member] | Other Assets and Liabilities Net [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.10% |
| C000012160 [Member] | Consumer Discretionary Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.10% |
| C000012160 [Member] | Consumer Staples Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.90% |
| C000012160 [Member] | Energy Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.50% |
| C000012160 [Member] | Financial Services Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.50% |
| C000012160 [Member] | Healthcare Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.60% |
| C000012160 [Member] | Industrial Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 19.90% |
| C000012160 [Member] | Real Estate Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.70% |
| C000012160 [Member] | Utilities Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.20% |
| C000012160 [Member] | Basic Materials [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000012160 [Member] | Telecommunications [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| C000012160 [Member] | Technology Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.90% |
| C000012160 [Member] | Other Assets and Liabilities Net [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.10% |
| C000102905 [Member] | Other Assets and Liabilities Net [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| C000102905 [Member] | Vanguard Variable Insurance Funds Equity Index Portfolio [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 20.80% |
| C000102905 [Member] | Vanguard Extended Market Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.40% |
| C000102905 [Member] | Vanguard Variable Insurance Funds Total Bond Market Index Portfolio [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 42.20% |
| C000102905 [Member] | Vanguard Total International Bond Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 18.20% |
| C000102905 [Member] | Vanguard Total International Stock Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 15.40% |
| C000102906 [Member] | Other Assets and Liabilities Net [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | (0.10%) |
| C000102906 [Member] | Vanguard Variable Insurance Funds Equity Index Portfolio [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 32% |
| C000102906 [Member] | Vanguard Extended Market Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.90% |
| C000102906 [Member] | Vanguard Variable Insurance Funds Total Bond Market Index Portfolio [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 28.30% |
| C000102906 [Member] | Vanguard Total International Bond Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.20% |
| C000102906 [Member] | Vanguard Total International Stock Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 22.70% |
| C000192542 [Member] | Other Assets and Liabilities Net [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| C000192542 [Member] | Vanguard Variable Insurance Funds Total Bond Market Index Portfolio [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 70% |
| C000192542 [Member] | Vanguard Total International Bond Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 30% |
| C000192543 [Member] | Other Assets and Liabilities Net [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| C000192543 [Member] | Vanguard FTSE All World ex US Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 28% |
| C000192543 [Member] | Vanguard Developed Markets Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 28% |
| C000192543 [Member] | Vanguard Emerging Markets Stock Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 19.40% |
| C000192543 [Member] | Vanguard European Stock Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.50% |
| C000192543 [Member] | Vanguard Pacific Stock Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.80% |
| C000192543 [Member] | Vanguard FTSE All World ex US Small Cap Index Fund Admiral Shares [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.20% |
| C000192543 [Member] | Vanguard FTSE Canada All Cap Index ETF [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.10% |
