Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	JOHN HANCOCK VARIABLE INSURANCE TRUST
Prospectus Date	rr_ProspectusDate	Apr. 28, 2025
Disciplined Value International Trust
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<span style="font-family:Arial Narrow;font-size:24pt;">Disciplined Value International Trust</span>
Objective [Heading]	rr_ObjectiveHeading	<span style="font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Investment objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	To seek long-term growth of capital.
Expense [Heading]	rr_ExpenseHeading	<span style="font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Fees and expenses</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the fund. The fees and expenses do not reflect fees and expenses of any variable insurance or variable annuities contract that may use the fund as its underlying investment option and would be higher if they did.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;margin-left:0.0pt;">Annual fund operating expenses (%) </span><span style="font-family:Arial Narrow;font-size:8pt;margin-left:0.0pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Portfolio turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During its most recent fiscal year, the fund’s portfolio turnover rate was 93% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	93.00%
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	<span style="font-family:Arial Narrow;font-size:8pt;">“Management fee” has been restated to reflect the contractual management fee schedule effective December 12, 2024.</span>
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Expense example</span>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The examples are intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The examples assume that $10,000 is invested in the fund for the periods indicated and then all shares are redeemed at the end of those periods. The examples also assume that the investment has a 5% return each year and that the fund’s operating expenses remain the same. The expense example does not reflect fees and expenses of any variable insurance contract that may use the fund as its underlying investment option and would be higher if they did. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Principal investment strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Board of Trustees can change the fund’s investment objective and strategies without shareholder approval. The fund pursues its investment objective by investing, under normal circumstances, at least 80% of its net assets (plus any borrowings for investment purposes) in a portfolio of equity and equity-related securities issued by non-U.S. companies of any capitalization size. The fund may invest in all types of equity and equity-related securities, including, without limitation, exchange-traded and over-the-counter common and preferred stocks, warrants, options, rights, convertible securities, sponsored and unsponsored depositary receipts and shares, trust certificates, participatory notes, limited partnership interests, shares of other investment companies (including exchange-traded funds (ETFs)), real estate investment trusts (REITs), and equity participations. An equity participation is a type of loan that gives the lender a portion of equity ownership in a property, in addition to principal and interest payments. A convertible security is a bond, debenture, note, preferred stock, or other security that may be converted into or exchanged for a prescribed amount of common stock of the same or a different issuer within a particular period of time at a specified price or formula. The fund defines non-U.S. companies as companies: (i) that are organized under the laws of a foreign country; (ii) whose principal trading market is in a foreign country; or (iii) that have a majority of their assets, or that derive a significant portion of their revenue or profits, from businesses, investments, or sales outside of the United States. The fund primarily will be invested in issuers located in countries with developed securities markets, but may also invest in issuers located in emerging and frontier markets. The fund may invest in securities denominated in the currencies of a variety of developed, emerging and frontier market countries. The fund generally invests in the equity securities of issuers believed by the manager to be undervalued in the marketplace, focusing on issuers that combine attractive valuations with catalysts for change. The manager applies a bottom-up stock selection process (i.e., one that focuses primarily on issuer specific factors) in managing the fund, using a combination of fundamental and quantitative analysis. In selecting investments for the fund, the manager considers various factors, such as price-to-book value, price-to-sales and earnings ratios, dividend yields, strength of management, and cash flow to identify securities that are trading at a price that appears to be lower than the issuer’s inherent value. The fund may (but is not required to) invest in derivatives, including put and call options, futures, forward contracts, and swaps, in lieu of investing directly in a security, currency or instrument, for hedging and nonhedging purposes, including reducing risk, obtaining efficient market exposure, and/or enhancing investment returns. The fund may invest up to 15% of its net assets in illiquid securities, including securities that are illiquid by virtue of the absence of a readily available market or legal or contractual restrictions on resale. The fund may participate as a purchaser in Initial Public Offerings (IPOs). An IPO is a company’s first offering of stock to the public. The fund may also seek to increase its income by lending portfolio securities. The manager will sell a stock when it no longer meets one or more investment criteria, either through obtaining target value or due to an adverse change in fundamentals or business momentum. Each holding has a target valuation established at purchase, which the manager constantly monitors and adjusts as appropriate. The fund may invest in cash or money market instruments for the purpose of meeting redemption requests or making other anticipated cash payments.
Risk [Heading]	rr_RiskHeading	<span style="font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Principal risks</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Past performance</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following information illustrates the variability of the fund’s returns and provides some indication of the risks of investing in the fund by showing changes in the fund’s performance from year to year and by showing how the fund’s average annual returns compared with a broad-based securities market index. Past performance does not indicate future results. All figures assume dividend reinvestment. The performance information below does not reflect fees and expenses of any variable insurance contract which may use JHVIT as its underlying investment option. If such fees and expenses had been reflected, performance would be lower.A note on performancePrior to February 12, 2020, the fund was managed by a different subadvisor pursuant to different investment strategies, and thus, the performance presented prior to this date should not be attributed to the current subadvisor. The fund’s performance shown below might have differed materially had the current subadvisor managed the fund prior to February 12, 2020.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial Narrow;font-size:9pt;">The following information illustrates the variability of the fund’s returns and provides some indication of the risks of investing in the fund by showing changes in the fund’s performance from year to year and by showing how the fund’s average annual returns compared with a broad-based securities market index. </span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="font-family:Arial Narrow;font-size:9pt;">Past performance does not indicate future results.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial Narrow;font-size:9pt;font-weight:bold;">Calendar year total returns (%)—Series I</span>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best quarter:Q4 202220.55%Worst quarter:Q1 2020-28.10%
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;margin-left:0.0pt;">Average annual total returns (%)—as of 12/31/2024</span>
Disciplined Value International Trust | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Many factors affect performance, and fund shares will fluctuate in price, meaning you could lose money.
Disciplined Value International Trust | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Disciplined Value International Trust | Cash And Cash Equivalents Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Cash and cash equivalents risk.  Under certain market conditions, such as during a rising stock market, rising interest rate or rising credit spread markets, the use of cash and/or cash equivalents, including money market instruments, could have a negative effect on the fund’s ability to achieve its investment objective and may negatively impact the fund’s performance.
Disciplined Value International Trust | Credit And Counterparty Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Credit and counterparty risk.  The counterparty to an over-the-counter derivatives contract or a borrower of fund securities may not make timely payments or otherwise honor its obligations.
Disciplined Value International Trust | Economic And Market Events Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Economic and market events risk.  Events in the U.S. and global financial markets, including actions taken by the U.S. Federal Reserve or foreign central banks to stimulate or stabilize economic growth, may at times result in unusually high market volatility, which could negatively impact performance. Reduced liquidity in credit and fixed-income markets could adversely affect issuers worldwide. Banks and financial services companies could suffer losses if interest rates rise or economic conditions deteriorate.
Disciplined Value International Trust | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Equity securities risk.  The price of equity securities may decline due to changes in a company’s financial condition or overall market conditions. Securities the manager believes are undervalued may never realize their full potential value, and in certain markets value stocks may underperform the market as a whole.
Disciplined Value International Trust | Exchange Traded Funds Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Exchange-traded funds (ETFs) risk.  The risks of owning shares of an ETF include the risks of owning the underlying securities the ETF holds. Lack of liquidity in an ETF could result in the ETF being more volatile than its underlying securities. An ETF’s shares could trade at a significant premium or discount to its net asset value (NAV). A fund bears ETF fees and expenses indirectly.
Disciplined Value International Trust | Foreign Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Foreign securities risk.  Less information may be publicly available regarding foreign issuers, including foreign government issuers. Foreign securities may be subject to foreign taxes and may be more volatile than U.S. securities. Currency fluctuations and political and economic developments may adversely impact the value of foreign securities. The risks of investing in foreign securities are magnified in emerging markets. Depositary receipts are subject to most of the risks associated with investing in foreign securities directly because the value of a depositary receipt is dependent upon the market price of the underlying foreign equity security. Depositary receipts are also subject to liquidity risk.
Disciplined Value International Trust | Frontier Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Frontier-market risk.  Frontier-market countries generally have smaller economies and less-developed capital markets and political systems than traditional emerging-market countries, which magnifies emerging-market risks.
Disciplined Value International Trust | Hedging Derivatives And Other Strategic Transactions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Hedging, derivatives, and other strategic transactions risk.  Hedging, derivatives, and other strategic transactions may increase a fund’s volatility and could produce disproportionate losses, potentially more than the fund’s principal investment. Risks of these transactions are different from and possibly greater than risks of investing directly in securities and other traditional instruments. Under certain market conditions, derivatives could become harder to value or sell and may become subject to liquidity risk (i.e., the inability to enter into closing transactions). Derivatives and other strategic transactions that the fund intends to utilize include: foreign currency forward contracts, futures contracts, swaps, equity-linked notes (equity-linked notes generally reflect the risks associated with their underlying securities, depend on the credit of the note’s issuer, may be privately placed, and may have a limited secondary market), and options. Foreign currency forward contracts, futures contracts, options and swaps generally are subject to counterparty risk. In addition, swaps may be subject to interest rate and settlement risk, and the risk of default of the underlying reference obligation. Derivatives associated with foreign currency transactions are subject to currency risk.
Disciplined Value International Trust | Illiquid And Restricted Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Illiquid and restricted securities risk.  Illiquid and restricted securities may be difficult to value and may involve greater risks than liquid securities. Illiquidity may have an adverse impact on a particular security’s market price and the fund’s ability to sell the security.
Disciplined Value International Trust | Initial Public Offerings Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Initial public offerings (IPOs) risk.  IPO share prices are frequently volatile and may significantly impact fund performance.
Disciplined Value International Trust | Investment Company Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Investment company securities risk.  Fund shareholders indirectly bear their proportionate share of the expenses of any investment company in which the fund invests. The total return on such investments will be reduced by the operating expenses and fees of such other investment companies, including advisory fees.
Disciplined Value International Trust | Large Company Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Large company risk.  Larger companies may grow more slowly than smaller companies or be slower to respond to business developments. Large-capitalization securities may underperform the market as a whole.
Disciplined Value International Trust | Liquidity Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Liquidity risk.  The extent (if at all) to which a security may be sold or a derivative position closed without negatively impacting its market value may be impaired by reduced market activity or participation, legal restrictions, or other economic and market impediments.
Disciplined Value International Trust | Operational And Cybersecurity Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Operational and cybersecurity risk.  Cybersecurity breaches may allow an unauthorized party to gain access to fund assets, customer data, or proprietary information, or cause a fund or its service providers to suffer data corruption or lose operational functionality. Similar incidents affecting issuers of a fund’s securities may negatively impact performance. Operational risk may arise from human error, error by third parties, communication errors, or technology failures, among other causes.
Disciplined Value International Trust | Participatory Notes Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Participatory notes risk.  Participatory notes (p-notes) represent interests in securities listed on certain foreign exchanges. Due to transaction costs and other expenses, p-notes will not replicate exactly the performance of their underlying securities. P-notes are general unsecured contractual obligations of the financial institutions issuing the notes and are subject to liquidity risk and a high degree of counterparty risk.
Disciplined Value International Trust | Preferred And Convertible Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Preferred and convertible securities risk.  Preferred stock dividends are payable only if declared by the issuer’s board. Preferred stock may be subject to redemption provisions. The market values of convertible securities tend to fall as interest rates rise and rise as interest rates fall. Convertible preferred stock’s value can depend heavily upon the underlying common stock’s value.
Disciplined Value International Trust | Real Estate Investment Trust Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Real estate investment trust (REIT) risk.  REITs, pooled investment vehicles that typically invest in real estate directly or in loans collateralized by real estate, carry risks associated with owning real estate, including the potential for a decline in value due to economic or market conditions.
Disciplined Value International Trust | Small And Mid Sized Company Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Small and mid-sized company risk.  Small and mid-sized companies are generally less established and may be more volatile than larger companies. Small and/or mid-capitalization securities may underperform the market as a whole.
Disciplined Value International Trust | Value Investment Style Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Value investment style risk.  Value securities may underperform the market as a whole, which may cause value-oriented funds to underperform equity funds with other investment strategies. Securities the manager believes are undervalued may never perform as expected.
Disciplined Value International Trust | Warrants Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Warrants risk.  The prices of warrants may not precisely reflect the prices of their underlying securities. Warrant holders do not receive dividends or have voting or credit rights. A warrant ceases to have value if not exercised prior to its expiration date.
Disciplined Value International Trust | Series I
Risk Return Abstract	rr_RiskReturnAbstract
Management fee	rr_ManagementFeesOverAssets	0.68%	[1]
Distribution and service (Rule 12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.05%
Other expenses	rr_OtherExpensesOverAssets	0.10%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.83%
1 year	rr_ExpenseExampleYear01	$ 85
3 years	rr_ExpenseExampleYear03	265
5 years	rr_ExpenseExampleYear05	460
10 years	rr_ExpenseExampleYear10	$ 1,025
2015	rr_AnnualReturn2015	(7.81%)
2016	rr_AnnualReturn2016	12.24%
2017	rr_AnnualReturn2017	17.14%
2018	rr_AnnualReturn2018	(15.03%)
2019	rr_AnnualReturn2019	12.33%
2020	rr_AnnualReturn2020	3.27%
2021	rr_AnnualReturn2021	13.06%
2022	rr_AnnualReturn2022	(4.77%)
2023	rr_AnnualReturn2023	19.96%
2024	rr_AnnualReturn2024	(0.38%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;margin-left:0.0pt;">Best quarter:</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2022
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	20.55%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;margin-left:0.0pt;">Worst quarter:</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(28.10%)
1 year	rr_AverageAnnualReturnYear01	(0.38%)
5 year	rr_AverageAnnualReturnYear05	5.85%
10 year	rr_AverageAnnualReturnYear10	4.39%
Disciplined Value International Trust | Series II
Risk Return Abstract	rr_RiskReturnAbstract
Management fee	rr_ManagementFeesOverAssets	0.68%	[1]
Distribution and service (Rule 12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.10%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.03%
1 year	rr_ExpenseExampleYear01	$ 105
3 years	rr_ExpenseExampleYear03	328
5 years	rr_ExpenseExampleYear05	569
10 years	rr_ExpenseExampleYear10	$ 1,259
1 year	rr_AverageAnnualReturnYear01	(0.56%)
5 year	rr_AverageAnnualReturnYear05	5.64%
10 year	rr_AverageAnnualReturnYear10	4.19%
Disciplined Value International Trust | NAV
Risk Return Abstract	rr_RiskReturnAbstract
Management fee	rr_ManagementFeesOverAssets	0.68%	[1]
Distribution and service (Rule 12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.10%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.78%
1 year	rr_ExpenseExampleYear01	$ 80
3 years	rr_ExpenseExampleYear03	249
5 years	rr_ExpenseExampleYear05	433
10 years	rr_ExpenseExampleYear10	$ 966
1 year	rr_AverageAnnualReturnYear01	(0.35%)
5 year	rr_AverageAnnualReturnYear05	5.89%
10 year	rr_AverageAnnualReturnYear10	4.45%
Disciplined Value International Trust | MSCI EAFE Index (reflects no deduction for fees, expenses, or taxes, except foreign withholding taxes on dividends)
Risk Return Abstract	rr_RiskReturnAbstract
1 year	rr_AverageAnnualReturnYear01	3.82%
5 year	rr_AverageAnnualReturnYear05	4.73%
10 year	rr_AverageAnnualReturnYear10	5.20%

[1] “Management fee” has been restated to reflect the contractual management fee schedule effective December 12, 2024.