XML 10 R3.htm IDEA: XBRL DOCUMENT v3.3.1.900
Label Element Value
Prospectus: rr_ProspectusTable  
Supplement Text Block jhvit-20151211_SupplementTextBlock
  
John Hancock Variable Insurance Trust
Supplement dated December 11, 2015
to the Prospectus dated April 27, 2015
 
Equity Income Trust
 
Effective January 1, 2016, the information found under the "Fees and Expenses" table and the "Expense Example" are amended and restated as follows to reflect the new advisory fee schedule:
 
Fees and expenses
 
This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. The fees and expenses do not reflect fees and expenses of any variable insurance contract that may use the fund as its underlying investment medium and would be higher if they did.
 
Annual fund operating expenses (%) (expenses that you pay each year as a percentage of the value of your investment)
Series I
Series II
Series NAV
Management fee 1
0.75
0.75
0.75
Distribution and service (Rule 12b-1) fees
0.05
0.25
0.00
Other expenses
0.03
0.03
0.03
Acquired fund fees and expenses 2
0.01
0.01
0.01
Total annual fund operating expenses 3
0.84
1.04
0.79
 
 
1
"Management fee" has been restated to reflect the contractual management fee schedule effective January 1, 2016.
  
 
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 net assets shown in the "Financial highlights" section of the fund's prospectus, which does not include "Acquired fund fees and expenses."
 
 
 Expense example
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 medium and would be higher if they did. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
 
Expenses ($)
Series I
Series II
Series NAV
1 year
86
106
81
3 years
268
331
252
5 years
466
574
439
10 years
1,037
1,271
978
 
 
Money Market Trust
Money Market Trust B
 
Conversion to Government Money Market Funds
 
On December 10, 2015, the Board of Trustees approved the conversion of the fund to a government money market fund as defined under Rule 2a-7 under the Investment Company Act of 1940, effective April 6, 2016 (the "Conversion Date"). In connection with this conversion, effective on the Conversion Date, the investment policies of the fund are amended and restated as follows:
 
The fund operates as a "government money market fund" in accordance with Rule 2a-7 under the Investment Company Act of 1940 and is managed in the following manner:

·
under normal market conditions, the fund invests at least 99.5% of its total assets in cash, U.S. Government securities and/or repurchase agreements that are fully collateralized by U.S. Government securities or cash

o
U.S. Government securities include both securities issued or guaranteed by the U.S. Treasury and securities issued by entities that are chartered or sponsored by Congress but are not issued or guaranteed by the U.S. Treasury

·
the fund seeks to maintain a stable net asset value ("NAV") of $1.00 per share and its portfolio is valued using the amortized cost method as permitted by Rule 2a-7

·
the fund invests only in U.S. dollar-denominated securities

·
the fund buys securities that have remaining maturities of 397 days or less (as calculated pursuant to Rule 2a-7)

·
the fund maintains a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life to maturity of 120 days or less

·
the fund must meet certain other criteria, including those relating to maturity, liquidity and credit quality

·
as a government money market fund, the fund is not subject to liquidity fees or redemption gates, although the Board may elect to impose such fees or gates in the future.

The fund generally expects to declare and pay dividends from net investment income on a daily basis on each share class as long as the income attributable to a class exceeds the expenses attributable to that class on each day. If class expenses exceed class income on any day, the fund will not pay a dividend on the class on that day and will resume paying dividends only when, on a future date, the accumulated net investment income of the class is positive. The fund has adopted this policy because, in the current investment environment of low interest rates, it may find that on any given day or on a number of consecutive days, its investment returns may be less than the expenses attributable to a class. For a more complete description of this policy, which can result in the fund not paying dividends on one or more classes for one or more periods that may be as short as a day or quite lengthy, see "General Information — Dividends" below. For a description of the allocation of expenses among fund share classes, see "Multiclass Pricing; Rule 12b-1 Plans" in the prospectus.
 
From time to time, the Advisor and its affiliates may reimburse or otherwise voluntarily reduce the fund's expenses or the Advisor may waive a portion of its management fee in an effort to maintain a net asset value of $1.00 per share, for the purpose of avoiding a negative yield or for the purpose of increasing the fund's yield during the period of the limitation. Any such expense reimbursements, reductions or waivers are voluntary and temporary and may be terminated by the Advisor at any time without notice.
 
You could lose money by investing in the fund. Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. 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. The fund's sponsor has no legal obligation to provide financial support to the fund, and you should not expect that the sponsor will provide financial support to the fund at any time.
 
In connection with this conversion, the Principal Investment Risks of the fund are amended to add the following additional risks, effective on the Conversion Date:
 
U.S. Treasury Obligations Risk. The market value of direct obligations of the U.S. Treasury may vary due to changes in interest rates. In addition, changes to the financial condition or credit rating of the U.S. government may cause the value of the fund's investments in obligations issued by the U.S. Treasury to decline.
 
U.S. Government Agency Obligations Risk. The fund invests in obligations issued by agencies and instrumentalities of the U.S. government. Government-sponsored entities such as Federal National Mortgage Association (Fannie Mae), Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal Home Loan Banks, although chartered or sponsored by Congress, are not funded by congressional appropriations and the debt securities that they issue are neither guaranteed nor issued by the U.S. government. Such debt securities are subject to the risk of default on the payment of interest and/or principal, similar to the debt securities of private issuers. The maximum potential liability of the issuers of some U.S. government obligations may greatly exceed their current resources, including any legal right to support from the U.S. government. Although the U.S. government has provided financial support to Fannie Mae and Freddie Mac in the past, there can be no assurance that it will support these or other government-sponsored entities in the future.
 
Redemption Risk. The fund may experience periods of heavy redemptions that could cause it to liquidate its assets at inopportune times or at a loss or depressed value, particularly during periods of declining or illiquid markets, and that could affect the fund's ability to maintain a $1.00 share price. Redemption risk is greater to the extent that the fund has investors with large shareholdings, short investment horizons or unpredictable cash flow needs. The redemption by one or more large shareholders of their holdings in the fund could cause the remaining shareholders in the fund to lose money. In addition, the fund may suspend redemptions and liquidate the fund when permitted by applicable regulations.
 
 
Effective on the Conversion Date, the information found under the "Fees and Expenses" table and the "Expense Example" are amended and restated as follows to reflect the new advisory fee schedule:
Money Market Trust
Fees and expenses
 
This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. The fees and expenses do not reflect fees and expenses of any variable insurance contract that may use the fund as its underlying investment medium and would be higher if they did.
 
Annual fund operating expenses (%) (expenses that you pay each year as a percentage of the value of your investment)
Series I
Series II
Series NAV
Management fee 1
0.35
0.35
0.35
Distribution and service (Rule 12b-1) fees
0.05
0.25
0.00
Other expenses
0.03
0.03
0.03 2
Total annual fund operating expenses
0.43
0.63
0.38
 
1
"Management fee" has been restated to reflect the contractual management fee schedule effective April 6, 2016.
2
"Other expenses" have been estimated for the first year of operations of the fund's Series NAV shares.
 

Expense example
 
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 medium and would be higher if they did. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
 
Expenses ($)
Series I
Series II
Series NAV
1 year
 44
 64
 39
3 years
 138
 202
 122
5 years
 241
 351
 213
10 years
 542
 786
 480
 

 
Money Market Trust B
 
Fees and expenses
 
This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. The fees and expenses do not reflect fees and expenses of any variable insurance contract that may use the fund as its underlying investment medium and would be higher if they did.
 
Annual fund operating expenses (%) (expenses that you pay each year as a percentage of the value of your investment)
Series NAV
Management fee 1
0.35
Distribution and service (Rule 12b-1) fees
0.00
Other expenses
0.04
Total annual fund operating expenses
0.39
Contractual expense reimbursement 2
-0.11
Total annual fund operating expenses after expense reimbursements
0.28
 
1
"Management fee" has been restated to reflect the contractual management fee schedule effective April 6, 2016.
2
The advisor has agreed to waive its advisory fee (or, if necessary, reimburse expenses of the fund) in an amount so that the fund's annual operating expenses do not exceed its "Total annual fund operating expenses after expense reimbursements" as shown in the table above. A fund's "Total annual fund operating expenses" includes all of its operating expenses including advisory and Rule 12b-1 fees, but excludes taxes, brokerage commissions, interest, short dividends, acquired fund fees, litigation and indemnification expenses and extraordinary expenses of the fund not incurred in the ordinary course of the fund's business. The advisor's obligation to provide the expense cap will remain in effect until April 30, 2016 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.
 

Expense example
 
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 medium and would be higher if they did. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 
 
Expenses ($)
Series NAV
1 year
  29
3 years
114
5 years
208
10 years
482
 
(JOHN HANCOCK VARIABLE INSURANCE TRUST - Equity Income Trust) | (Equity Income Trust)  
Prospectus: rr_ProspectusTable  
Expense [Heading] rr_ExpenseHeading

Fees and expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. The fees and expenses do not reflect fees and expenses of any variable insurance contract that may use the fund as its underlying investment medium and would be higher if they did.
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)
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 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 medium and would be higher if they did. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
(JOHN HANCOCK VARIABLE INSURANCE TRUST - Equity Income Trust) | (Equity Income Trust) | Series I  
Prospectus: rr_ProspectusTable  
Management fee rr_ManagementFeesOverAssets 0.75% [1]
Distribution and service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.05%
Other expenses rr_OtherExpensesOverAssets 0.03%
Acquired fund fees and expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.01% [2]
Total annual fund operating expenses rr_ExpensesOverAssets 0.84% [3]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 86
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 268
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 466
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,037
(JOHN HANCOCK VARIABLE INSURANCE TRUST - Equity Income Trust) | (Equity Income Trust) | Series II  
Prospectus: rr_ProspectusTable  
Management fee rr_ManagementFeesOverAssets 0.75% [1]
Distribution and service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.03%
Acquired fund fees and expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.01% [2]
Total annual fund operating expenses rr_ExpensesOverAssets 1.04% [3]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 106
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 331
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 574
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,271
(JOHN HANCOCK VARIABLE INSURANCE TRUST - Equity Income Trust) | (Equity Income Trust) | Series NAV  
Prospectus: rr_ProspectusTable  
Management fee rr_ManagementFeesOverAssets 0.75% [1]
Distribution and service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.03%
Acquired fund fees and expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.01% [2]
Total annual fund operating expenses rr_ExpensesOverAssets 0.79% [3]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 81
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 252
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 439
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 978
(JOHN HANCOCK VARIABLE INSURANCE TRUST - Money Market Trust) | (Money Market Trust)  
Prospectus: rr_ProspectusTable  
Expense [Heading] rr_ExpenseHeading

Fees and expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. The fees and expenses do not reflect fees and expenses of any variable insurance contract that may use the fund as its underlying investment medium and would be higher if they did.

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)
Other Expenses, New Fund, Based on Estimates [Text] rr_OtherExpensesNewFundBasedOnEstimates "Other expenses" have been estimated for the first year of operations of the fund's Series NAV shares.
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 medium 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 Narrative [Text Block] rr_StrategyNarrativeTextBlock
The fund operates as a "government money market fund" in accordance with Rule 2a-7 under the Investment Company Act of 1940 and is managed in the following manner:

·
under normal market conditions, the fund invests at least 99.5% of its total assets in cash, U.S. Government securities and/or repurchase agreements that are fully collateralized by U.S. Government securities or cash

o
U.S. Government securities include both securities issued or guaranteed by the U.S. Treasury and securities issued by entities that are chartered or sponsored by Congress but are not issued or guaranteed by the U.S. Treasury

·
the fund seeks to maintain a stable net asset value ("NAV") of $1.00 per share and its portfolio is valued using the amortized cost method as permitted by Rule 2a-7

·
the fund invests only in U.S. dollar-denominated securities

·
the fund buys securities that have remaining maturities of 397 days or less (as calculated pursuant to Rule 2a-7)

·
the fund maintains a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life to maturity of 120 days or less

·
the fund must meet certain other criteria, including those relating to maturity, liquidity and credit quality

·
as a government money market fund, the fund is not subject to liquidity fees or redemption gates, although the Board may elect to impose such fees or gates in the future.

The fund generally expects to declare and pay dividends from net investment income on a daily basis on each share class as long as the income attributable to a class exceeds the expenses attributable to that class on each day. If class expenses exceed class income on any day, the fund will not pay a dividend on the class on that day and will resume paying dividends only when, on a future date, the accumulated net investment income of the class is positive. The fund has adopted this policy because, in the current investment environment of low interest rates, it may find that on any given day or on a number of consecutive days, its investment returns may be less than the expenses attributable to a class. For a more complete description of this policy, which can result in the fund not paying dividends on one or more classes for one or more periods that may be as short as a day or quite lengthy, see "General Information — Dividends" below. For a description of the allocation of expenses among fund share classes, see "Multiclass Pricing; Rule 12b-1 Plans" in the prospectus.
 
From time to time, the Advisor and its affiliates may reimburse or otherwise voluntarily reduce the fund's expenses or the Advisor may waive a portion of its management fee in an effort to maintain a net asset value of $1.00 per share, for the purpose of avoiding a negative yield or for the purpose of increasing the fund's yield during the period of the limitation. Any such expense reimbursements, reductions or waivers are voluntary and temporary and may be terminated by the Advisor at any time without notice.
 
You could lose money by investing in the fund. Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. 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. The fund's sponsor has no legal obligation to provide financial support to the fund, and you should not expect that the sponsor will provide financial support to the fund at any time.
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

U.S. Treasury Obligations Risk. The market value of direct obligations of the U.S. Treasury may vary due to changes in interest rates. In addition, changes to the financial condition or credit rating of the U.S. government may cause the value of the fund's investments in obligations issued by the U.S. Treasury to decline.

U.S. Government Agency Obligations Risk. The fund invests in obligations issued by agencies and instrumentalities of the U.S. government. Government-sponsored entities such as Federal National Mortgage Association (Fannie Mae), Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal Home Loan Banks, although chartered or sponsored by Congress, are not funded by congressional appropriations and the debt securities that they issue are neither guaranteed nor issued by the U.S. government. Such debt securities are subject to the risk of default on the payment of interest and/or principal, similar to the debt securities of private issuers. The maximum potential liability of the issuers of some U.S. government obligations may greatly exceed their current resources, including any legal right to support from the U.S. government. Although the U.S. government has provided financial support to Fannie Mae and Freddie Mac in the past, there can be no assurance that it will support these or other government-sponsored entities in the future.

Redemption Risk. The fund may experience periods of heavy redemptions that could cause it to liquidate its assets at inopportune times or at a loss or depressed value, particularly during periods of declining or illiquid markets, and that could affect the fund's ability to maintain a $1.00 share price. Redemption risk is greater to the extent that the fund has investors with large shareholdings, short investment horizons or unpredictable cash flow needs. The redemption by one or more large shareholders of their holdings in the fund could cause the remaining shareholders in the fund to lose money. In addition, the fund may suspend redemptions and liquidate the fund when permitted by applicable regulations.
(JOHN HANCOCK VARIABLE INSURANCE TRUST - Money Market Trust) | (Money Market Trust) | Series I  
Prospectus: rr_ProspectusTable  
Management fee rr_ManagementFeesOverAssets 0.35% [4]
Distribution and service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.05%
Other expenses rr_OtherExpensesOverAssets 0.03%
Total annual fund operating expenses rr_ExpensesOverAssets 0.43%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 44
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 138
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 241
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 542
(JOHN HANCOCK VARIABLE INSURANCE TRUST - Money Market Trust) | (Money Market Trust) | Series II  
Prospectus: rr_ProspectusTable  
Management fee rr_ManagementFeesOverAssets 0.35% [4]
Distribution and service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.03%
Total annual fund operating expenses rr_ExpensesOverAssets 0.63%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 64
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 202
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 351
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 786
(JOHN HANCOCK VARIABLE INSURANCE TRUST - Money Market Trust) | (Money Market Trust) | Series NAV  
Prospectus: rr_ProspectusTable  
Management fee rr_ManagementFeesOverAssets 0.35% [4]
Distribution and service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.03% [5]
Total annual fund operating expenses rr_ExpensesOverAssets 0.38%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 39
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 122
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 213
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 480
(JOHN HANCOCK VARIABLE INSURANCE TRUST - Money Market Trust B) | (Money Market Trust B)  
Prospectus: rr_ProspectusTable  
Expense [Heading] rr_ExpenseHeading

Fees and expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. The fees and expenses do not reflect fees and expenses of any variable insurance contract that may use the fund as its underlying investment medium and would be higher if they did.

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 April 30, 2016
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 medium 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 Narrative [Text Block] rr_StrategyNarrativeTextBlock
The fund operates as a "government money market fund" in accordance with Rule 2a-7 under the Investment Company Act of 1940 and is managed in the following manner:

·
under normal market conditions, the fund invests at least 99.5% of its total assets in cash, U.S. Government securities and/or repurchase agreements that are fully collateralized by U.S. Government securities or cash

o
U.S. Government securities include both securities issued or guaranteed by the U.S. Treasury and securities issued by entities that are chartered or sponsored by Congress but are not issued or guaranteed by the U.S. Treasury

·
the fund seeks to maintain a stable net asset value ("NAV") of $1.00 per share and its portfolio is valued using the amortized cost method as permitted by Rule 2a-7

·
the fund invests only in U.S. dollar-denominated securities

·
the fund buys securities that have remaining maturities of 397 days or less (as calculated pursuant to Rule 2a-7)

·
the fund maintains a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life to maturity of 120 days or less

·
the fund must meet certain other criteria, including those relating to maturity, liquidity and credit quality

·
as a government money market fund, the fund is not subject to liquidity fees or redemption gates, although the Board may elect to impose such fees or gates in the future.

The fund generally expects to declare and pay dividends from net investment income on a daily basis on each share class as long as the income attributable to a class exceeds the expenses attributable to that class on each day. If class expenses exceed class income on any day, the fund will not pay a dividend on the class on that day and will resume paying dividends only when, on a future date, the accumulated net investment income of the class is positive. The fund has adopted this policy because, in the current investment environment of low interest rates, it may find that on any given day or on a number of consecutive days, its investment returns may be less than the expenses attributable to a class. For a more complete description of this policy, which can result in the fund not paying dividends on one or more classes for one or more periods that may be as short as a day or quite lengthy, see "General Information — Dividends" below. For a description of the allocation of expenses among fund share classes, see "Multiclass Pricing; Rule 12b-1 Plans" in the prospectus.
 
From time to time, the Advisor and its affiliates may reimburse or otherwise voluntarily reduce the fund's expenses or the Advisor may waive a portion of its management fee in an effort to maintain a net asset value of $1.00 per share, for the purpose of avoiding a negative yield or for the purpose of increasing the fund's yield during the period of the limitation. Any such expense reimbursements, reductions or waivers are voluntary and temporary and may be terminated by the Advisor at any time without notice.
 
You could lose money by investing in the fund. Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. 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. The fund's sponsor has no legal obligation to provide financial support to the fund, and you should not expect that the sponsor will provide financial support to the fund at any time.
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

U.S. Treasury Obligations Risk. The market value of direct obligations of the U.S. Treasury may vary due to changes in interest rates. In addition, changes to the financial condition or credit rating of the U.S. government may cause the value of the fund's investments in obligations issued by the U.S. Treasury to decline.

U.S. Government Agency Obligations Risk. The fund invests in obligations issued by agencies and instrumentalities of the U.S. government. Government-sponsored entities such as Federal National Mortgage Association (Fannie Mae), Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal Home Loan Banks, although chartered or sponsored by Congress, are not funded by congressional appropriations and the debt securities that they issue are neither guaranteed nor issued by the U.S. government. Such debt securities are subject to the risk of default on the payment of interest and/or principal, similar to the debt securities of private issuers. The maximum potential liability of the issuers of some U.S. government obligations may greatly exceed their current resources, including any legal right to support from the U.S. government. Although the U.S. government has provided financial support to Fannie Mae and Freddie Mac in the past, there can be no assurance that it will support these or other government-sponsored entities in the future.

Redemption Risk. The fund may experience periods of heavy redemptions that could cause it to liquidate its assets at inopportune times or at a loss or depressed value, particularly during periods of declining or illiquid markets, and that could affect the fund's ability to maintain a $1.00 share price. Redemption risk is greater to the extent that the fund has investors with large shareholdings, short investment horizons or unpredictable cash flow needs. The redemption by one or more large shareholders of their holdings in the fund could cause the remaining shareholders in the fund to lose money. In addition, the fund may suspend redemptions and liquidate the fund when permitted by applicable regulations.
(JOHN HANCOCK VARIABLE INSURANCE TRUST - Money Market Trust B) | (Money Market Trust B) | Series NAV  
Prospectus: rr_ProspectusTable  
Management fee rr_ManagementFeesOverAssets 0.35% [6]
Distribution and service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.04%
Total annual fund operating expenses rr_ExpensesOverAssets 0.39%
Contractual expense reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.11%) [7]
Total annual fund operating expenses after expense reimbursements rr_NetExpensesOverAssets 0.28%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 29
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 114
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 208
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 482
[1] "Management fee" has been restated to reflect the contractual management fee schedule effective January 1, 2016.
[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 net assets shown in the "Financial highlights" section of the fund's prospectus, which does not include "Acquired fund fees and expenses."
[4] "Management fee" has been restated to reflect the contractual management fee schedule effective April 6, 2016.
[5] "Other expenses" have been estimated for the first year of operations of the fund's Series NAV shares.
[6] "Management fee" has been restated to reflect the contractual management fee schedule effective April 6, 2016.
[7] The advisor has agreed to waive its advisory fee (or, if necessary, reimburse expenses of the fund) in an amount so that the fund's annual operating expenses do not exceed its "Total annual fund operating expenses after expense reimbursements" as shown in the table above. A fund's "Total annual fund operating expenses" includes all of its operating expenses including advisory and Rule 12b-1 fees, but excludes taxes, brokerage commissions, interest, short dividends, acquired fund fees, litigation and indemnification expenses and extraordinary expenses of the fund not incurred in the ordinary course of the fund's business. The advisor's obligation to provide the expense cap will remain in effect until April 30, 2016 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.