Label	Element	Value
Prospectus [Line Items]	rr_ProspectusLineItems
Document Type	dei_DocumentType	497
Document Period End Date	dei_DocumentPeriodEndDate	Dec. 31, 2022
Entity Registrant Name	dei_EntityRegistrantName	JOHN HANCOCK VARIABLE INSURANCE TRUST
Entity Central Index Key	dei_EntityCentralIndexKey	0000756913
Entity Inv Company Type	dei_EntityInvCompanyType	N-1A
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Mar. 30, 2023
Document Effective Date	dei_DocumentEffectiveDate	Apr. 01, 2023
(Disciplined Value International Trust)
Prospectus [Line Items]	rr_ProspectusLineItems
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual fund operating expenses (%) (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	July 31, 2024
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	The “Total annual fund operating expenses” shown may not correlate to the fund’s ratios of expenses to average daily net assets shown in the “Financial highlights” section of the fund’s prospectus, which does not include “Acquired fund fees and expenses.”
Expense Example [Heading]	rr_ExpenseExampleHeading	Expense example
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:
(Disciplined Value International Trust) | Series I
Prospectus [Line Items]	rr_ProspectusLineItems
Management Fees (as a percentage of Assets)	rr_ManagementFeesOverAssets	0.70%	[1]
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.05%
Other Expenses (as a percentage of Assets):	rr_OtherExpensesOverAssets	0.11%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%	[2]
Expenses (as a percentage of Assets)	rr_ExpensesOverAssets	0.87%	[3]
Fee Waiver or Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[4]
Net Expenses (as a percentage of Assets)	rr_NetExpensesOverAssets	0.86%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 88
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	277
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	481
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 1,072
(Disciplined Value International Trust) | Series II
Prospectus [Line Items]	rr_ProspectusLineItems
Management Fees (as a percentage of Assets)	rr_ManagementFeesOverAssets	0.70%	[1]
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses (as a percentage of Assets):	rr_OtherExpensesOverAssets	0.11%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%	[2]
Expenses (as a percentage of Assets)	rr_ExpensesOverAssets	1.07%	[3]
Fee Waiver or Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[4]
Net Expenses (as a percentage of Assets)	rr_NetExpensesOverAssets	1.06%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 108
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	339
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	589
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 1,305
(Disciplined Value International Trust) | Series NAV
Prospectus [Line Items]	rr_ProspectusLineItems
Management Fees (as a percentage of Assets)	rr_ManagementFeesOverAssets	0.70%	[1]
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses (as a percentage of Assets):	rr_OtherExpensesOverAssets	0.11%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%	[2]
Expenses (as a percentage of Assets)	rr_ExpensesOverAssets	0.82%	[3]
Fee Waiver or Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[4]
Net Expenses (as a percentage of Assets)	rr_NetExpensesOverAssets	0.81%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 83
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	261
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	454
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 1,013

[1] “Management fee” has been restated to reflect the contractual management fee schedule effective April 1, 2023.

[2] “Acquired fund fees and expenses” are based on indirect net expenses associated with the fund’s investments in underlying investment companies.

[3] The “Total annual fund operating expenses” shown may not correlate to the fund’s ratios of expenses to average daily net assets shown in the “Financial highlights” section of the fund’s prospectus, which does not include “Acquired fund fees and expenses.”

[4] The advisor contractually agrees to waive a portion of its management fee and/or reimburse expenses for the fund and certain other John Hancock funds according to an asset level breakpoint schedule that is based on the aggregate net assets of all the funds participating in the waiver or reimbursement, including the fund (the participating portfolios). This waiver equals, on an annualized basis, 0.0100% of that portion of the aggregate net assets of all the participating portfolios that exceeds $75 billion but is less than or equal to $125 billion; 0.0125% of that portion of the aggregate net assets of all the participating portfolios that exceeds $125 billion but is less than or equal to $150 billion; 0.0150% of that portion of the aggregate net assets of all the participating portfolios that exceeds $150 billion but is less than or equal to $175 billion; 0.0175% of that portion of the aggregate net assets of all the participating portfolios that exceeds $175 billion but is less than or equal to $200 billion; 0.0200% of that portion of the aggregate net assets of all the participating portfolios that exceeds $200 billion but is less than or equal to $225 billion; and 0.0225% of that portion of the aggregate net assets of all the participating portfolios that exceeds $225 billion. The amount of the reimbursement is calculated daily and allocated among all the participating portfolios in proportion to the daily net assets of each participating portfolio. During its most recent fiscal year, the fund’s reimbursement amounted to 0.01% of the fund’s average daily net assets. This agreement expires on July 31, 2024, unless renewed by mutual agreement of the fund and the advisor based upon a determination that this is appropriate under the circumstances at that time.