Label

Element

Value

Prospectus:

rr_ProspectusTable

Supplement Text Block

jhit-20190626_SupplementTextBlock

Prospectus Supplement

John Hancock Investment Trust

John Hancock Balanced Fund (the "fund")

Supplement dated June 26, 2019 to the current Prospectus, as may be supplemented

Effective August 1, 2019, the "Shareholder fees" table and the "Expense example" table in the "Fund summary" section are amended and restated as follows to reflect that the maximum front-end sales charge on Class A shares of the fund is reduced:

Shareholder fees (%) (fees paid directly from your investment)	A	B	C	I	R1	R2	R3	R4	R5	R6
Maximum front-end sales charge (load) on purchases, as a % of purchase price	4.50	None	None	None	None	None	None	None	None	None
Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less	1.00 (on certain purchases, including those of $250,000 or more)	5.00	1.00	None	None	None	None	None	None	None
Small account fee (for fund account balances under $1,000) ($)	20	20	20	None	None	None	None	None	None	None

EXPENSE EXAMPLE

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. Please see below a hypothetical example showing the expenses of a $10,000 investment for the time periods indicated and then, except as shown below, assuming you sell all of your shares at the end of those periods. The example assumes a 5% average annual return and that fund expenses will not change over the periods. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expenses ($)	A		B		C	I	R1	R2	R3	R4	R5	R6
Shares		Sold	Not Sold	Sold	Not Sold
1 year	553	679	179	279	179	79	145	119	134	94	74	68
3 years	774	856	556	556	556	248	451	374	420	317	232	217
5 years	1,013	1,158	958	958	958	432	781	648	728	558	405	378
10 years	1,696	1,899	1,899	2,083	2,083	965	1,712	1,431	1,601	1,249	906	846

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund)

Prospectus:

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Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees (%) (fees paid directly from your investment)

Expense Example [Heading]

rr_ExpenseExampleHeading

EXPENSE EXAMPLE

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. Please see below a hypothetical example showing the expenses of a $10,000 investment for the time periods indicated and then, except as shown below, assuming you sell all of your shares at the end of those periods. The example assumes a 5% average annual return and that fund expenses will not change over the periods. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

Sold

Expense Example, No Redemption, By Year, Caption [Text]

rr_ExpenseExampleNoRedemptionByYearCaption

Not Sold

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund) | Class A

Prospectus:

rr_ProspectusTable

Maximum front-end sales charge (load) on purchases, as a % of purchase price

rr_MaximumCumulativeSalesChargeOverOther

4.50%

Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[1]

Small account fee (for fund account balances under $1,000) ($)

rr_ShareholderFeeOther

$ 20

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

553

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

774

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,013

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,696

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund) | Class B

Prospectus:

rr_ProspectusTable

Maximum front-end sales charge (load) on purchases, as a % of purchase price

rr_MaximumCumulativeSalesChargeOverOther

none

Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less

rr_MaximumDeferredSalesChargeOverOther

5.00%

Small account fee (for fund account balances under $1,000) ($)

rr_ShareholderFeeOther

$ 20

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

679

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

856

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,158

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,899

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

179

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

556

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

958

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

$ 1,899

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund) | Class C

Prospectus:

rr_ProspectusTable

Maximum front-end sales charge (load) on purchases, as a % of purchase price

rr_MaximumCumulativeSalesChargeOverOther

none

Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less

rr_MaximumDeferredSalesChargeOverOther

1.00%

Small account fee (for fund account balances under $1,000) ($)

rr_ShareholderFeeOther

$ 20

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

279

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

556

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

958

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,083

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

179

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

556

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

958

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

$ 2,083

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund) | Class I

Prospectus:

rr_ProspectusTable

Maximum front-end sales charge (load) on purchases, as a % of purchase price

rr_MaximumCumulativeSalesChargeOverOther

none

Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less

rr_MaximumDeferredSalesChargeOverOther

none

Small account fee (for fund account balances under $1,000) ($)

rr_ShareholderFeeOther

none

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

79

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

248

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

432

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 965

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund) | Class R1

Prospectus:

rr_ProspectusTable

Maximum front-end sales charge (load) on purchases, as a % of purchase price

rr_MaximumCumulativeSalesChargeOverOther

none

Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less

rr_MaximumDeferredSalesChargeOverOther

none

Small account fee (for fund account balances under $1,000) ($)

rr_ShareholderFeeOther

none

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

145

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

451

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

781

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,712

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund) | Class R2

Prospectus:

rr_ProspectusTable

Maximum front-end sales charge (load) on purchases, as a % of purchase price

rr_MaximumCumulativeSalesChargeOverOther

none

Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less

rr_MaximumDeferredSalesChargeOverOther

none

Small account fee (for fund account balances under $1,000) ($)

rr_ShareholderFeeOther

none

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

119

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

374

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

648

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,431

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund) | Class R3

Prospectus:

rr_ProspectusTable

Maximum front-end sales charge (load) on purchases, as a % of purchase price

rr_MaximumCumulativeSalesChargeOverOther

none

Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less

rr_MaximumDeferredSalesChargeOverOther

none

Small account fee (for fund account balances under $1,000) ($)

rr_ShareholderFeeOther

none

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

134

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

420

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

728

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,601

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund) | Class R4

Prospectus:

rr_ProspectusTable

Maximum front-end sales charge (load) on purchases, as a % of purchase price

rr_MaximumCumulativeSalesChargeOverOther

none

Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less

rr_MaximumDeferredSalesChargeOverOther

none

Small account fee (for fund account balances under $1,000) ($)

rr_ShareholderFeeOther

none

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

94

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

317

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

558

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,249

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund) | Class R5

Prospectus:

rr_ProspectusTable

Maximum front-end sales charge (load) on purchases, as a % of purchase price

rr_MaximumCumulativeSalesChargeOverOther

none

Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less

rr_MaximumDeferredSalesChargeOverOther

none

Small account fee (for fund account balances under $1,000) ($)

rr_ShareholderFeeOther

none

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

74

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

232

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

405

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 906

(John Hancock Balanced Fund - Classes A, B, C, I and R1-R6) | (John Hancock Balanced Fund) | Class R6

Prospectus:

rr_ProspectusTable

Maximum front-end sales charge (load) on purchases, as a % of purchase price

rr_MaximumCumulativeSalesChargeOverOther

none

Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less

rr_MaximumDeferredSalesChargeOverOther

none

Small account fee (for fund account balances under $1,000) ($)

rr_ShareholderFeeOther

none

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

68

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

217

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

378

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 846

[1] (on certain purchases, including those of $250,000 or more)