| Form N-CSR Cover | 6 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | BlackRock Variable Series Funds II, Inc. |
| Entity Central Index Key | 0001738072 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 6 Months Ended |
| Jun. 30, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | BlackRock Variable Series Funds II, Inc. |
| Entity Central Index Key | 0001738072 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| C000202342 | |
| Shareholder Report [Line Items] | |
| Fund Name | BlackRock High Yield V.I. Fund |
| Class Name | Class I Shares |
| Trading Symbol | HICUI |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about BlackRock High Yield V.I. Fund (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 blackrock.com/fundreports |
| Additional Information Phone Number | (800) 441-7762 |
| Additional Information Website | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com/fundreports</span></span>" id="sjs-B19"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com/fundreports</span></span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (based on a hypothetical $10,000 investment) Class name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class I Shares $28 0.55% |
| Expenses Paid, Amount | $ 28 |
| Expense Ratio, Percent | 0.55% |
| Performance Past Does Not Indicate Future [Text] | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">Past performance is not an indication of future results. </span>Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption or sale of fund shares. Visit <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com</span></span> for more recent performance information.</p>" id="sjs-B23"><p style="box-sizing: border-box; color: rgb(0, 0, 0); display: block; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">Past performance is not an indication of future results. </span>Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption or sale of fund shares. Visit <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com</span></span> for more recent performance information.</p> |
| Average Annual Return [Table Text Block] | Fund performance Average annual total returns Key Fund statistics Average Annual Total Returns 6-Month Total Returns 1 Year 5 Years 10 Years Class I Shares ................................................................................................................................................................ 3.24 % 10.70 % 4.42 % 4.25 % Bloomberg U.S. Universal Index ................................................................................................................................................................ (0.28 ) 3.47 0.11 1.63 Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index ................................................................................................................................................................ 2.58 10.43 3.90 4.30 Net Assets ................................................................................................................................................................ $931,958,572 Number of Portfolio Holdings ................................................................................................................................................................ 1,206 Portfolio Turnover Rate ................................................................................................................................................................ 34% On September 17, 2018, the Fund acquired all of the assets, subject to the liabilities, of BlackRock High Yield V.I. Fund (the “Predecessor Fund”), a series of BlackRock Variable Series Funds, Inc., through a tax-free reorganization (the “Reorganization”). The Predecessor Fund is the performance and accounting survivor of the Reorganization. Assuming transaction costs, if any, and other operating expenses, including investment advisory fees. Average annual total returns do not reflect insurance-related fees and expenses. The Fund has added the Bloomberg U.S. Universal Index in response to new regulatory requirements. |
| No Deduction of Taxes [Text Block] | |
| Performance Table Market Index Changed [Text Block] | |
| Material Change Description [Text Block] | |
| Updated Performance Information Location [Text Block] | |
| AssetsNet | $ 931,958,572 |
| Holdings Count | Holding | 1,206 |
| InvestmentCompanyPortfolioTurnover | 34% |
| Holdings [Text Block] | Credit quality allocation Credit Rating Footnote Reference Percent of Total Investments Footnote Reference A ................................................................................................................................................................ 0.3 % BBB/Baa ................................................................................................................................................................ 5.2 BB/Ba ................................................................................................................................................................ 38.2 B ................................................................................................................................................................ 46.9 CCC/Caa ................................................................................................................................................................ 8.5 CC/Ca ................................................................................................................................................................ 0.1 NR ................................................................................................................................................................ 0.8 Footnote Description Footnote (a) For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated NR are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change. Footnote (b) Excludes short-term securities. |
| C000202343 | |
| Shareholder Report [Line Items] | |
| Fund Name | BlackRock High Yield V.I. Fund |
| Class Name | Class III Shares |
| Trading Symbol | HCIII |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about BlackRock High Yield V.I. Fund (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 blackrock.com/fundreports |
| Additional Information Phone Number | (800) 441-7762 |
| Additional Information Website | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com/fundreports</span></span>" id="sjs-B42"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com/fundreports</span></span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (based on a hypothetical $10,000 investment) Class name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class III Shares $40 0.79% |
| Expenses Paid, Amount | $ 40 |
| Expense Ratio, Percent | 0.79% |
| Performance Past Does Not Indicate Future [Text] | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">Past performance is not an indication of future results. </span>Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption or sale of fund shares. Visit <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com</span></span> for more recent performance information.</p>" id="sjs-B46"><p style="box-sizing: border-box; color: rgb(0, 0, 0); display: block; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">Past performance is not an indication of future results. </span>Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption or sale of fund shares. Visit <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com</span></span> for more recent performance information.</p> |
| Average Annual Return [Table Text Block] | Fund performance Average annual total returns Key Fund statistics Average Annual Total Returns 6-Month Total Returns 1 Year 5 Years 10 Years Class III Shares ................................................................................................................................................................ 3.12 % 10.61 % 4.17 % 4.00 % Bloomberg U.S. Universal Index ................................................................................................................................................................ (0.28 ) 3.47 0.11 1.63 Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index ................................................................................................................................................................ 2.58 10.43 3.90 4.30 Net Assets ................................................................................................................................................................ $931,958,572 Number of Portfolio Holdings ................................................................................................................................................................ 1,206 Portfolio Turnover Rate ................................................................................................................................................................ 34% On September 17, 2018, the Fund acquired all of the assets, subject to the liabilities, of BlackRock High Yield V.I. Fund (the “Predecessor Fund”), a series of BlackRock Variable Series Funds, Inc., through a tax-free reorganization (the “Reorganization”). The Predecessor Fund is the performance and accounting survivor of the Reorganization. Assuming transaction costs, if any, and other operating expenses, including investment advisory fees. Average annual total returns do not reflect insurance-related fees and expenses. The Fund has added the Bloomberg U.S. Universal Index in response to new regulatory requirements. |
| No Deduction of Taxes [Text Block] | |
| Performance Table Market Index Changed [Text Block] | |
| Material Change Description [Text Block] | |
| Updated Performance Information Location [Text Block] | |
| AssetsNet | $ 931,958,572 |
| Holdings Count | Holding | 1,206 |
| InvestmentCompanyPortfolioTurnover | 34% |
| Holdings [Text Block] | Credit quality allocation Credit Rating Footnote Reference Percent of Total Investments Footnote Reference A ................................................................................................................................................................ 0.3 % BBB/Baa ................................................................................................................................................................ 5.2 BB/Ba ................................................................................................................................................................ 38.2 B ................................................................................................................................................................ 46.9 CCC/Caa ................................................................................................................................................................ 8.5 CC/Ca ................................................................................................................................................................ 0.1 NR ................................................................................................................................................................ 0.8 Footnote Description Footnote (a) For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated NR are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change. Footnote (b) Excludes short-term securities. |
| C000202344 | |
| Shareholder Report [Line Items] | |
| Fund Name | BlackRock Total Return V.I. Fund |
| Class Name | Class I Shares |
| Trading Symbol | CRBDI |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about BlackRock Total Return V.I. Fund (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 blackrock.com/fundreports |
| Additional Information Phone Number | (800) 441-7762 |
| Additional Information Website | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com/fundreports</span></span>" id="sjs-B65"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com/fundreports</span></span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (based on a hypothetical $10,000 investment) Class name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class I Shares $24 0.48% |
| Expenses Paid, Amount | $ 24 |
| Expense Ratio, Percent | 0.48% |
| Performance Past Does Not Indicate Future [Text] | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">Past performance is not an indication of future results. </span>Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption or sale of fund shares. Visit <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com</span></span> for more recent performance information.</p>" id="sjs-B69"><p style="box-sizing: border-box; color: rgb(0, 0, 0); display: block; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">Past performance is not an indication of future results. </span>Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption or sale of fund shares. Visit <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com</span></span> for more recent performance information.</p> |
| Average Annual Return [Table Text Block] | Fund performance Average annual total returns Average Annual Total Returns 6-Month Total Returns 1 Year 5 Years 10 Years Class I Shares ................................................................................................................................................................ (0.26 )% 2.63 % (0.02 )% 1.40 % Bloomberg U.S. Aggregate Bond Index ................................................................................................................................................................ (0.71 ) 2.63 (0.23 ) 1.35 On September 17, 2018, the Fund acquired all of the assets, subject to the liabilities, of BlackRock Total Return V.I. Fund (the “Predecessor Fund”), a series of BlackRock Variable Series Funds, Inc., through a tax-free reorganization (the “Reorganization”). The Predecessor Fund is the performance and accounting survivor of the Reorganization. Assuming transaction costs, if any, and other operating expenses, including investment advisory fees. Average annual total returns do not reflect insurance-related fees and expenses. |
| No Deduction of Taxes [Text Block] | |
| Performance Table Market Index Changed [Text Block] | |
| Material Change Description [Text Block] | |
| Updated Performance Information Location [Text Block] | |
| AssetsNet | $ 866,624,701 |
| Holdings Count | Holding | 2,032 |
| InvestmentCompanyPortfolioTurnover | 364% |
| Additional Fund Statistics [Text Block] | Key Fund statistics |
| Holdings [Text Block] | Portfolio composition Credit quality allocation Investment Type Percent of Total Investments Footnote Reference U.S. Government Sponsored Agency Securities ................................................................................................................................................................ 30.9 % Corporate Bonds ................................................................................................................................................................ 23.2 U.S. Treasury Obligations ................................................................................................................................................................ 22.7 Investment Companies ................................................................................................................................................................ 14.7 Foreign Government Obligations ................................................................................................................................................................ 3.9 Asset-Backed Securities ................................................................................................................................................................ 2.2 Non-Agency Mortgage-Backed Securities ................................................................................................................................................................ 1.0 Foreign Agency Obligations ................................................................................................................................................................ 0.7 Municipal Bonds ................................................................................................................................................................ 0.6 Common Stocks ................................................................................................................................................................ 0.1 Other Footnote Reference ................................................................................................................................................................ 0.0 Footnote Reference Credit Rating Footnote Reference Percent of Total Investments Footnote Reference AAA/Aaa Footnote Reference ................................................................................................................................................................ 56.0 % AA/Aa ................................................................................................................................................................ 2.4 A ................................................................................................................................................................ 22.6 BBB/Baa ................................................................................................................................................................ 16.3 BB/Ba ................................................................................................................................................................ 1.3 B ................................................................................................................................................................ 0.2 CCC/Caa ................................................................................................................................................................ 0.1 CC/Ca ................................................................................................................................................................ 0.2 C ................................................................................................................................................................ 0.1 D ................................................................................................................................................................ 0.0 Footnote Reference NR ................................................................................................................................................................ 0.8 Footnote Description Footnote (a) Excludes short-term securities, short investments and options, if any. Footnote (b) Ten largest investment types are presented. Additional investment types are found in Other. Footnote (c) Rounds to less than 0.1%. Footnote (d) For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated NR are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change. Footnote (e) The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa. |
| C000202345 | |
| Shareholder Report [Line Items] | |
| Fund Name | BlackRock Total Return V.I. Fund |
| Class Name | Class III Shares |
| Trading Symbol | CBIII |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about BlackRock Total Return V.I. Fund (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 blackrock.com/fundreports |
| Additional Information Phone Number | (800) 441-7762 |
| Additional Information Website | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com/fundreports</span></span>" id="sjs-B89"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com/fundreports</span></span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (based on a hypothetical $10,000 investment) Class name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class III Shares $39 0.79% |
| Expenses Paid, Amount | $ 39 |
| Expense Ratio, Percent | 0.79% |
| Performance Past Does Not Indicate Future [Text] | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">Past performance is not an indication of future results. </span>Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption or sale of fund shares. Visit <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com</span></span> for more recent performance information.</p>" id="sjs-B93"><p style="box-sizing: border-box; color: rgb(0, 0, 0); display: block; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">Past performance is not an indication of future results. </span>Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption or sale of fund shares. Visit <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify;">blackrock.com</span></span> for more recent performance information.</p> |
| Average Annual Return [Table Text Block] | Fund performance Average annual total returns Average Annual Total Returns 6-Month Total Returns 1 Year 5 Years 10 Years Class III Shares ................................................................................................................................................................ (0.44 )% 2.29 % (0.33 )% 1.09 % Bloomberg U.S. Aggregate Bond Index ................................................................................................................................................................ (0.71 ) 2.63 (0.23 ) 1.35 On September 17, 2018, the Fund acquired all of the assets, subject to the liabilities, of BlackRock Total Return V.I. Fund (the “Predecessor Fund”), a series of BlackRock Variable Series Funds, Inc., through a tax-free reorganization (the “Reorganization”). The Predecessor Fund is the performance and accounting survivor of the Reorganization. Assuming transaction costs, if any, and other operating expenses, including investment advisory fees. Average annual total returns do not reflect insurance-related fees and expenses. |
| No Deduction of Taxes [Text Block] | |
| Performance Table Market Index Changed [Text Block] | |
| Material Change Description [Text Block] | |
| Updated Performance Information Location [Text Block] | |
| AssetsNet | $ 866,624,701 |
| Holdings Count | Holding | 2,032 |
| InvestmentCompanyPortfolioTurnover | 364% |
| Additional Fund Statistics [Text Block] | Key Fund statistics |
| Holdings [Text Block] | Portfolio composition Credit quality allocation Investment Type Percent of Total Investments Footnote Reference U.S. Government Sponsored Agency Securities ................................................................................................................................................................ 30.9 % Corporate Bonds ................................................................................................................................................................ 23.2 U.S. Treasury Obligations ................................................................................................................................................................ 22.7 Investment Companies ................................................................................................................................................................ 14.7 Foreign Government Obligations ................................................................................................................................................................ 3.9 Asset-Backed Securities ................................................................................................................................................................ 2.2 Non-Agency Mortgage-Backed Securities ................................................................................................................................................................ 1.0 Foreign Agency Obligations ................................................................................................................................................................ 0.7 Municipal Bonds ................................................................................................................................................................ 0.6 Common Stocks ................................................................................................................................................................ 0.1 Other Footnote Reference ................................................................................................................................................................ 0.0 Footnote Reference Credit Rating Footnote Reference Percent of Total Investments Footnote Reference AAA/Aaa Footnote Reference ................................................................................................................................................................ 56.0 % AA/Aa ................................................................................................................................................................ 2.4 A ................................................................................................................................................................ 22.6 BBB/Baa ................................................................................................................................................................ 16.3 BB/Ba ................................................................................................................................................................ 1.3 B ................................................................................................................................................................ 0.2 CCC/Caa ................................................................................................................................................................ 0.1 CC/Ca ................................................................................................................................................................ 0.2 C ................................................................................................................................................................ 0.1 D ................................................................................................................................................................ 0.0 Footnote Reference NR ................................................................................................................................................................ 0.8 Footnote Description Footnote (a) Excludes short-term securities, short investments and options, if any. Footnote (b) Ten largest investment types are presented. Additional investment types are found in Other. Footnote (c) Rounds to less than 0.1%. Footnote (d) For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated NR are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change. Footnote (e) The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa. |
| Shareholder Report, Average Annual Return (Details) | 6 Months Ended | 12 Months Ended | 60 Months Ended | 120 Months Ended |
| Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | |
| Without Sales Load [Member] | C000202342 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 3.24% | 10.70% | 4.42% | 4.25% |
| Without Sales Load [Member] | C000202343 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 3.12% | 10.61% | 4.17% | 4% |
| Without Sales Load [Member] | C000202344 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | (0.26%) | 2.63% | (0.02%) | 1.40% |
| Without Sales Load [Member] | C000202345 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | (0.44%) | 2.29% | (0.33%) | 1.09% |
| FR Notes - Benchmark total return 6 months w/o sales charge | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | (0.28%) | |||
| FR Notes - Benchmark total return 1 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 3.47% | |||
| FR Notes - Benchmark total return 5 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 0.11% | |||
| FR Notes - Benchmark total return 10 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 1.63% | |||
| FR Notes - Benchmark total return 6 months w/o sales charge | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | (0.28%) | |||
| FR Notes - Benchmark total return 1 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 3.47% | |||
| FR Notes - Benchmark total return 5 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 0.11% | |||
| FR Notes - Benchmark total return 10 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 1.63% | |||
| FR Notes - Benchmark total return 6 months w/o sales charge | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | (0.71%) | |||
| FR Notes - Benchmark total return 1 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 2.63% | |||
| FR Notes - Benchmark total return 5 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | (0.23%) | |||
| FR Notes - Benchmark total return 10 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 1.35% | |||
| FR Notes - Benchmark total return 6 months w/o sales charge | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | (0.71%) | |||
| FR Notes - Benchmark total return 1 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 2.63% | |||
| FR Notes - Benchmark total return 5 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | (0.23%) | |||
| FR Notes - Benchmark total return 10 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 1.35% | |||
| FR Notes - Benchmark total return 6 months w/o sales charge - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 2.58% | |||
| FR Notes - Benchmark total return 1 year - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 10.43% | |||
| FR Notes - Benchmark total return 5 year - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 3.90% | |||
| FR Notes - Benchmark total return 10 year - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 4.30% | |||
| FR Notes - Benchmark total return 6 months w/o sales charge - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 2.58% | |||
| FR Notes - Benchmark total return 1 year - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 10.43% | |||
| FR Notes - Benchmark total return 5 year - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 3.90% | |||
| FR Notes - Benchmark total return 10 year - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 4.30% |
| Shareholder Report, Holdings (Details) | Jun. 30, 2024 |
| C000202342 | A | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.30% |
| C000202342 | BBB/Baa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.20% |
| C000202342 | BB/Ba | |
| Holdings [Line Items] | |
| Percent of Total Investments | 38.20% |
| C000202342 | B | |
| Holdings [Line Items] | |
| Percent of Total Investments | 46.90% |
| C000202342 | CCC/Caa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.50% |
| C000202342 | CC/Ca | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| C000202342 | NR | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.80% |
| C000202343 | A | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.30% |
| C000202343 | BBB/Baa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.20% |
| C000202343 | BB/Ba | |
| Holdings [Line Items] | |
| Percent of Total Investments | 38.20% |
| C000202343 | B | |
| Holdings [Line Items] | |
| Percent of Total Investments | 46.90% |
| C000202343 | CCC/Caa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.50% |
| C000202343 | CC/Ca | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| C000202343 | NR | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.80% |
| C000202344 | A | |
| Holdings [Line Items] | |
| Percent of Total Investments | 22.60% |
| C000202344 | BBB/Baa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 16.30% |
| C000202344 | BB/Ba | |
| Holdings [Line Items] | |
| Percent of Total Investments | 1.30% |
| C000202344 | B | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.20% |
| C000202344 | CCC/Caa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| C000202344 | CC/Ca | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.20% |
| C000202344 | NR | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.80% |
| C000202344 | AAA/Aaa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 56% |
| C000202344 | AA/Aa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 2.40% |
| C000202344 | C | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| C000202344 | D | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0% |
| C000202344 | U.S. Government Sponsored Agency Securities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 30.90% |
| C000202344 | Corporate Bonds | |
| Holdings [Line Items] | |
| Percent of Total Investments | 23.20% |
| C000202344 | U.S. Treasury Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 22.70% |
| C000202344 | Investment Companies | |
| Holdings [Line Items] | |
| Percent of Total Investments | 14.70% |
| C000202344 | Foreign Government Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.90% |
| C000202344 | Asset-Backed Securities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 2.20% |
| C000202344 | Non-Agency Mortgage-Backed Securities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 1% |
| C000202344 | Foreign Agency Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.70% |
| C000202344 | Municipal Bonds | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.60% |
| C000202344 | Common Stocks | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| C000202344 | Other | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0% |
| C000202345 | A | |
| Holdings [Line Items] | |
| Percent of Total Investments | 22.60% |
| C000202345 | BBB/Baa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 16.30% |
| C000202345 | BB/Ba | |
| Holdings [Line Items] | |
| Percent of Total Investments | 1.30% |
| C000202345 | B | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.20% |
| C000202345 | CCC/Caa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| C000202345 | CC/Ca | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.20% |
| C000202345 | NR | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.80% |
| C000202345 | AAA/Aaa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 56% |
| C000202345 | AA/Aa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 2.40% |
| C000202345 | C | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| C000202345 | D | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0% |
| C000202345 | U.S. Government Sponsored Agency Securities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 30.90% |
| C000202345 | Corporate Bonds | |
| Holdings [Line Items] | |
| Percent of Total Investments | 23.20% |
| C000202345 | U.S. Treasury Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 22.70% |
| C000202345 | Investment Companies | |
| Holdings [Line Items] | |
| Percent of Total Investments | 14.70% |
| C000202345 | Foreign Government Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.90% |
| C000202345 | Asset-Backed Securities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 2.20% |
| C000202345 | Non-Agency Mortgage-Backed Securities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 1% |
| C000202345 | Foreign Agency Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.70% |
| C000202345 | Municipal Bonds | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.60% |
| C000202345 | Common Stocks | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.10% |
| C000202345 | Other | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0% |
