| Shareholder Report | 6 Months Ended |
| Jun. 30, 2024 USD ($) Holding |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | Vanguard Variable Insurance Funds |
| Entity Central Index Key | 0000857490 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| C000012146 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - Balanced Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Balanced Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - Balanced Portfolio $11 0.21% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 11 |
| Expense Ratio, Percent | 0.21% |
| AssetsNet | $ 3,402,000,000 |
| Holdings Count | Holding | 1,368 |
| InvestmentCompanyPortfolioTurnover | 35% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $3,402 Number of Portfolio Holdings 1,368 Portfolio Turnover Rate 35% |
| 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 (as of June 30, 2024) Communications 7.1% Consumer Discretionary 8.0% Consumer Staples 4.0% Energy 4.2% Financials 18.6% Health Care 10.0% Industrials 5.4% Materials 1.3% Real Estate 1.2% Technology 22.9% Utilities 5.1% Other 11.1% Other Assets and Liabilities—Net 1.1% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012153 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - Capital Growth Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Capital Growth Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - Capital Growth Portfolio $18 0.34% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 18 |
| Expense Ratio, Percent | 0.34% |
| AssetsNet | $ 2,019,000,000 |
| Holdings Count | Holding | 111 |
| InvestmentCompanyPortfolioTurnover | 2% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $2,019 Number of Portfolio Holdings 111 Portfolio Turnover Rate 2% |
| Holdings [Text Block] | This table reflects the Fund's investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets (as of June 30, 2024) Communication Services 5.6% Consumer Discretionary 8.7% Consumer Staples 0.3% Energy 2.1% Financials 6.5% Health Care 31.3% Industrials 11.3% Information Technology 29.4% Materials 1.1% Other Assets and Liabilities—Net 3.7% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012154 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - Diversified Value Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Diversified Value Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - Diversified Value Portfolio $15 0.28% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 15 |
| Expense Ratio, Percent | 0.28% |
| AssetsNet | $ 1,309,000,000 |
| Holdings Count | Holding | 125 |
| InvestmentCompanyPortfolioTurnover | 17% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $1,309 Number of Portfolio Holdings 125 Portfolio Turnover Rate 17% |
| 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 (as of June 30, 2024) Communication Services 6.5% Consumer Discretionary 9.1% Consumer Staples 4.5% Energy 7.5% Financials 20.3% Health Care 13.1% Industrials 8.6% Information Technology 21.0% Materials 1.1% Real Estate 1.2% Utilities 1.1% Other Assets and Liabilities—Net 6.0% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012155 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - Equity Income Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Equity Income Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - Equity Income Portfolio $15 0.29% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 15 |
| Expense Ratio, Percent | 0.29% |
| AssetsNet | $ 2,043,000,000 |
| Holdings Count | Holding | 178 |
| InvestmentCompanyPortfolioTurnover | 23% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $2,043 Number of Portfolio Holdings 178 Portfolio Turnover Rate 23% |
| 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 (as of June 30, 2024) Communication Services 2.0% Consumer Discretionary 5.2% Consumer Staples 11.2% Energy 10.7% Financials 20.2% Health Care 13.7% Industrials 10.6% Information Technology 10.5% Materials 3.5% Real Estate 2.1% Utilities 7.3% Other Assets and Liabilities—Net 3.0% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012157 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - Growth Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Growth Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - Growth Portfolio $19 0.34% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 19 |
| Expense Ratio, Percent | 0.34% |
| AssetsNet | $ 1,470,000,000 |
| Holdings Count | Holding | 57 |
| InvestmentCompanyPortfolioTurnover | 28% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $1,470 Number of Portfolio Holdings 57 Portfolio Turnover Rate 28% |
| Holdings [Text Block] | This table reflects the Fund's investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets (as of June 30, 2024) Communication Services 13.5% Consumer Discretionary 12.8% Financials 8.9% Health Care 9.4% Industrials 5.9% Information Technology 47.0% Real Estate 2.2% Other Assets and Liabilities—Net 0.3% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012158 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - High Yield Bond Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about High Yield Bond Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - High Yield Bond Portfolio $12 0.24% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 12 |
| Expense Ratio, Percent | 0.24% |
| AssetsNet | $ 750,000,000 |
| Holdings Count | Holding | 898 |
| InvestmentCompanyPortfolioTurnover | 26% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $750 Number of Portfolio Holdings 898 Portfolio Turnover Rate 26% |
| 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 (as of June 30, 2024) Consumer Discretionary 15.9% Communications 13.1% Energy 11.2% Materials 9.1% Industrials 9.0% Financials 8.5% Health Care 7.4% Technology 6.3% U.S. Government and Agency Obligations 4.8% Consumer Staples 3.5% Floating Rate Loan Interests 3.0% Utilities 2.1% Real Estate 1.4% Other Assets and Liabilities—Net Footnote Reference 4.7% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012159 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - International Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about International Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - International Portfolio $16 0.31% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 16 |
| Expense Ratio, Percent | 0.31% |
| AssetsNet | $ 3,040,000,000 |
| Holdings Count | Holding | 137 |
| InvestmentCompanyPortfolioTurnover | 10% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $3,040 Number of Portfolio Holdings 137 Portfolio Turnover Rate 10% |
| 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 (as of June 30, 2024) Europe 47.6% Asia 29.3% North America 16.8% South America 2.0% Oceania 1.2% Other Assets and Liabilities—Net 3.1% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012147 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - Money Market Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Money Market Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - Money Market Portfolio $8 0.15% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 8 |
| Expense Ratio, Percent | 0.15% |
| AssetsNet | $ 1,237,000,000 |
| Holdings Count | Holding | 272 |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $1,237 Number of Portfolio Holdings 272 |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012149 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - Short-Term Investment-Grade Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Short-Term Investment-Grade Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - Short-Term Investment-Grade Portfolio $7 0.14% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 7 |
| Expense Ratio, Percent | 0.14% |
| AssetsNet | $ 2,155,000,000 |
| Holdings Count | Holding | 1,950 |
| InvestmentCompanyPortfolioTurnover | 34% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $2,155 Number of Portfolio Holdings 1,950 Portfolio Turnover Rate 34% |
| 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 (as of June 30, 2024) Corporate Bonds 81.6% U.S. Government and Agency Obligations 10.2% Asset-Backed/Commercial Mortgage-Backed Securities 4.5% Sovereign Bonds 1.8% Other 0.2% Other Assets and Liabilities—Net Footnote Reference 1.7% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012150 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - Small Company Growth Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Small Company Growth Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - Small Company Growth Portfolio $15 0.29% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 15 |
| Expense Ratio, Percent | 0.29% |
| AssetsNet | $ 1,471,000,000 |
| Holdings Count | Holding | 522 |
| InvestmentCompanyPortfolioTurnover | 27% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $1,471 Number of Portfolio Holdings 522 Portfolio Turnover Rate 27% |
| 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 (as of June 30, 2024) Communication Services 5.1% Consumer Discretionary 11.4% Consumer Staples 2.1% Energy 2.6% Financials 6.5% Health Care 24.3% Industrials 21.8% Information Technology 18.9% Materials 2.6% Real Estate 0.5% Utilities 0.4% Other Assets and Liabilities—Net 3.8% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
| C000012151 | |
| Shareholder Report [Line Items] | |
| Fund Name | Variable Insurance Funds - Total Bond Market Index Portfolio |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Total Bond Market Index Portfolio (the "Fund") for the period of January 1, 2024, to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund 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 six months? (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 - Total Bond Market Index Portfolio $7 0.14% Footnote Reference Footnote Description Footnote 1 Annualized. |
| Expenses Paid, Amount | $ 7 |
| Expense Ratio, Percent | 0.14% |
| AssetsNet | $ 4,359,000,000 |
| Holdings Count | Holding | 10,734 |
| InvestmentCompanyPortfolioTurnover | 21% |
| Additional Fund Statistics [Text Block] | Fund Statistics (as of June 30, 2024) Fund Net Assets (in millions) $4,359 Number of Portfolio Holdings 10,734 Portfolio Turnover Rate 21% |
| Holdings [Text Block] | This table reflects the Fund's investments, including short-term investments and other assets and liabilities. Portfolio Composition % of Net Assets (as of June 30, 2024) U.S. Government and Agency Obligations 66.4% Corporate Bonds 26.2% Sovereign Bonds 3.5% Asset-Backed/Commercial Mortgage-Backed Securities 2.5% Taxable Municipal Bonds 0.6% Other Assets and Liabilities—Net Footnote Reference 0.8% |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | https://personal1.vanguard.com/ngf-next-gen-form-webapp/fund-literature |
