Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	JOHN HANCOCK INVESTMENT TRUST
Prospectus Date	rr_ProspectusDate	Mar. 01, 2025
Class NAV | John Hancock ESG Large Cap Core Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<span style="color:#000000;font-family:Arial Narrow;font-size:24pt;">John Hancock ESG Large Cap Core Fund</span>
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Investment objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	To seek long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;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 you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial Narrow;font-size:8pt;font-weight:bold;margin-left:0.0pt;">Shareholder fees (%) </span><span style="color:#000000;font-family:Arial Narrow;font-size:8pt;margin-left:0.0pt;">(fees paid directly from your investment)</span>
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>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial Narrow;font-size:8pt;">February 28, 2026</span><span style="font-family:Arial Narrow;font-size:8pt;">July 31, 2026</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;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 and may result in higher taxes when fund shares are held in a taxable account. 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 30% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	30.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Expense example</span>
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 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:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Principal investment strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal market conditions, the fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in equity securities of large-capitalization companies or sectors that meet the manager’s sustainability criteria. The fund considers large-capitalization companies to be those companies in the capitalization range of the S&P 500 Index, which was approximately $5.77 billion to $3,785 billion as of December 31, 2024. Equity securities include common and preferred stocks and their equivalents. The manager seeks companies meeting its sustainability criteria with high quality characteristics including strong environmental, social, and governance (ESG) records. The manager employs a bottom-up financial analysis that includes a review of ESG issues and how they may impact stock valuation or performance. ESG factors reflect a variety of key sustainability issues that can influence company risks and opportunities and span a range of metrics including board diversity, climate change policies, and supply chain and human rights policies. Companies that meet the manager’s ESG requirements or sustainability criteria typically have strong sustainability data and policy reporting, for example publishing a comprehensive corporate sustainability report. The fund may also invest up to 20% of its total assets in the equity securities of foreign issuers, including American Depositary Receipts (ADRs) and Global Depositary Receipts (GDRs). The fund may focus its investments in a particular sector or sectors of the economy. The manager may sell stocks for several reasons, including when the stock no longer meets the manager’s ESG or sustainability criteria, or when the stock declines in value and no longer reflects the manager’s investment thesis. As part of its ESG analysis, the manager currently identifies certain industries and business activities as too environmentally risky or as presenting social outcomes that are too unattractive to warrant investment consideration. The manager employs qualitative and quantitative screens to exclude or restrict these types of investments. The fund does not invest in companies that are primarily engaged in fossil fuel production or fossil fuel-powered generation based on a company's total gross revenue unless the company demonstrates a plan to transition to a low carbon business model that the manager finds credible. At a minimum, to be considered for investment, these companies must derive a material portion of current revenue from renewable energy or enabling technology and have no commitments to invest in new fossil fuel exploration, production, storage, transport (excluding distribution), trading, or refining capacity, new fossil fuel-based power generation without emissions capture, or new nuclear power generation. The fund will not invest in any companies that derive a material proportion of their total gross revenue from business activities related to agricultural biotechnology, coal and certain types of mining, pornography, private prisons, tar sands (e.g., oil sands), arctic drilling, tobacco, casinos and gaming, and weapons/firearms. The fund also will not invest in any companies with major recent or ongoing controversies involving animal welfare, environmental, governance, human rights, product safety, or workplace matters. When assessing a controversy, the manager will consider the potential for a controversy to adversely impact a company’s financial performance or cause harm to the company’s stakeholders. The manager employs active shareowner engagement to raise environmental, social, and governance issues with the management of select portfolio companies. Through this effort, the manager seeks to encourage company managements toward greater transparency, accountability, disclosure, and commitment to ESG issues.
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial Narrow;font-size:10pt;font-weight:bold;">Principal risks</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;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 (before and after taxes) does not indicate future results. All figures assume dividend reinvestment. Performance information is updated daily, monthly, and quarterly and may be obtained by calling 800-344-1029 between 8:00 a.m. and 7:00 p.m., Eastern time, on most business days.A note on performanceClass C shares commenced operations on June 6, 2016. Because Class NAV shares had not commenced operations as of the date of this prospectus, the returns shown are those of Class C shares, except that they do not include sales charges and would be lower if they did. Returns for Class NAV shares would have been substantially similar to returns of Class C shares because each share class is invested in the same portfolio of securities and returns would differ only to the extent that expenses of the classes are different. To the extent expenses of a class would have been higher than expenses of Class C shares for the periods shown, performance would have been lower.Please note that after-tax returns reflect the highest individual federal marginal income-tax rate in effect as of the date provided and do not reflect any state or local taxes. Your actual after-tax returns may be different. After-tax returns are not relevant to shares held in an IRA, 401(k), or other tax-advantaged investment plan.
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 Availability Phone [Text]	rr_PerformanceAvailabilityPhone	<span style="font-family:Arial Narrow;font-size:9pt;">800-344-1029 between 8:00 </span><span style="font-family:Arial Narrow;font-size:9pt;font-variant:small-caps;">a.m.</span><span style="font-family:Arial Narrow;font-size:9pt;"> and 7:00</span><span style="font-family:Arial Narrow;font-size:9pt;line-height:12pt;"> </span><span style="font-family:Arial Narrow;font-size:9pt;font-variant:small-caps;">p.m.</span><span style="font-family:Arial Narrow;font-size:9pt;">, Eastern time, on most business days.</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="font-family:Arial Narrow;font-size:9pt;"> Past performance (before and after taxes) 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 (%)—Class NAV</span>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best quarter:Q2 202021.98%Worst quarter:Q1 2020-21.13%
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>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="color:#000000;font-family:Arial Narrow;font-size:9pt;">Please note that after-tax returns reflect the highest individual federal marginal income-tax rate in effect as of the date provided and do not reflect any state or local taxes.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial Narrow;font-size:9pt;"> Your actual after-tax returns may be different. After-tax returns are not relevant to shares held in an IRA, 401(k), or other </span><span style="color:#000000;font-family:Arial Narrow;font-size:9pt;">tax-advantaged investment plan.</span>
Class NAV | John Hancock ESG Large Cap Core Fund | 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.
Class NAV | John Hancock ESG Large Cap Core Fund | 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.
Class NAV | John Hancock ESG Large Cap Core Fund | 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.
Class NAV | John Hancock ESG Large Cap Core Fund | 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.
Class NAV | John Hancock ESG Large Cap Core Fund | ESG Investing Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	ESG investing risk.  Incorporating ESG criteria and investing primarily in instruments that have certain ESG characteristics, as determined by the manager, carries the risk that the fund may perform differently, including underperforming, funds that do not utilize an ESG investment strategy, or funds that utilize different ESG criteria.
Class NAV | John Hancock ESG Large Cap Core Fund | 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. 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.
Class NAV | John Hancock ESG Large Cap Core Fund | Information Technology Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Information technology companies risk.  Information technology companies can be significantly affected by rapid obsolescence, short product cycles, competition from new market entrants, and heightened cybersecurity risk, among other factors.
Class NAV | John Hancock ESG Large Cap Core Fund | 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.
Class NAV | John Hancock ESG Large Cap Core Fund | 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 without negatively impacting its market value may be impaired by reduced market activity or participation, legal restrictions, or other economic and market impediments.
Class NAV | John Hancock ESG Large Cap Core Fund | 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.
Class NAV | John Hancock ESG Large Cap Core Fund | Preferred Stock Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Preferred stock risk.  Preferred stock generally ranks senior to common stock with respect to dividends and liquidation but ranks junior to debt securities. Unlike interest payments on debt securities, preferred stock dividends are payable only if declared by the issuer’s board of directors. Preferred stock may be subject to optional or mandatory redemption provisions.
Class NAV | John Hancock ESG Large Cap Core Fund | Sector Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Sector risk.  When a fund focuses its investments in certain sectors of the economy, its performance may be driven largely by sector performance and could fluctuate more widely than if the fund were invested more evenly across sectors.
Class NAV | John Hancock ESG Large Cap Core Fund | Class NAV
Risk Return Abstract	rr_RiskReturnAbstract
Maximum front-end sales charge (load)	rr_MaximumCumulativeSalesChargeOverOther	none
Maximum deferred sales charge (load)	rr_MaximumDeferredSalesChargeOverOther	none
Management fee	rr_ManagementFeesOverAssets	0.75%
Other expenses	rr_OtherExpensesOverAssets	0.21%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.96%
Contractual expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.21%)	[1]
Total annual fund operating expenses after expense reimbursements	rr_NetExpensesOverAssets	0.75%
1 year	rr_ExpenseExampleYear01	$ 77
3 years	rr_ExpenseExampleYear03	285
5 years	rr_ExpenseExampleYear05	510
10 years	rr_ExpenseExampleYear10	$ 1,159
2017	rr_AnnualReturn2017	15.39%
2018	rr_AnnualReturn2018	(0.97%)
2019	rr_AnnualReturn2019	29.38%
2020	rr_AnnualReturn2020	17.32%
2021	rr_AnnualReturn2021	28.79%
2022	rr_AnnualReturn2022	(20.41%)
2023	rr_AnnualReturn2023	20.34%
2024	rr_AnnualReturn2024	15.85%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="color:#000000;font-family:Arial Narrow;font-size:8pt;font-weight:bold;margin-left:0.0pt;">Best quarter:</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	21.98%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="color:#000000;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	(21.13%)
1 year	rr_AverageAnnualReturnYear01	15.85%
5 year	rr_AverageAnnualReturnYear05	10.89%
Since inception	rr_AverageAnnualReturnSinceInception	11.84%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jun. 06, 2016
Class NAV | John Hancock ESG Large Cap Core Fund | Return After Taxes on Distributions | Class NAV
Risk Return Abstract	rr_RiskReturnAbstract
1 year	rr_AverageAnnualReturnYear01	13.37%
5 year	rr_AverageAnnualReturnYear05	10.15%
Since inception	rr_AverageAnnualReturnSinceInception	11.29%
Class NAV | John Hancock ESG Large Cap Core Fund | Return After Taxes on Distributions and Sale of Shares | Class NAV
Risk Return Abstract	rr_RiskReturnAbstract
1 year	rr_AverageAnnualReturnYear01	11.20%
5 year	rr_AverageAnnualReturnYear05	8.63%
Since inception	rr_AverageAnnualReturnSinceInception	9.71%
Class NAV | John Hancock ESG Large Cap Core Fund | S&P 500 Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 year	rr_AverageAnnualReturnYear01	25.02%
5 year	rr_AverageAnnualReturnYear05	14.53%
Since inception	rr_AverageAnnualReturnSinceInception	14.77%

[1] The advisor contractually agrees to reduce its management fee or, if necessary, make payment to the fund in an amount equal to the amount by which expenses of the fund exceed 0.75% of average daily net assets of the fund. For purposes of this agreement, “expenses of the fund” means all fund expenses, excluding (a) taxes, (b) brokerage commissions, (c) interest expense, (d) litigation and indemnification expenses and other extraordinary expenses not incurred in the ordinary course of the fund’s business, (e) class-specific expenses, (f) borrowing costs, (g) prime brokerage fees, (h) acquired fund fees and expenses paid indirectly, and (i) short dividend expense. This agreement expires on February 28, 2026, 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. The advisor also 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, 2026, 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.