Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	TRANSAMERICA FUNDS
Prospectus Date	rr_ProspectusDate	Mar. 01, 2022
Class I2 | Transamerica Small Cap Value
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<span style="color:#000000;font-family:Times New Roman;font-size:11pt;font-weight:bold;">Transamerica Small Cap Value</span>
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Investment Objective:</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Seeks long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">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. 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:Times New Roman;font-size:9pt;font-weight:bold;margin-left:0%;">Shareholder Fees (fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Times New Roman;font-size:9pt;font-weight:bold;">Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">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 the most recent fiscal year, the portfolio turnover rate for the fund was 94% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	94.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">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.The Example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the fund’s operating expenses remain the same. 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:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">Principal Investment Strategies:</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The fund’s sub-adviser, Peregrine Capital Management, LLC (the “sub-adviser”) invests, under normal circumstances, at least 80% of the fund’s net assets (plus the amount of borrowings, if any, for investment purposes) in equity securities of small-capitalization companies. The fund generally considers a small-capitalization company to be a company with a market capitalization within the range of the Russell 2000® Value Index1at the time of initial purchase. As of December 31, 2021, the market capitalization range of the Russell 2000® Value Index was between $33.8 million and $14 billion. The equity securities in which the fund invests are primarily common stocks of U.S. companies.The sub-adviser uses a proprietary, quantitative screening process designed to identify the least expensive small cap stocks across each sector.  This screening process narrows the investment universe and allows the sub-adviser to focus its fundamental research and analysis on the stocks that the sub-adviser believes are the most undervalued relative to their respective sector peer group. Fundamental research is primarily conducted through financial statement analysis, meetings with company management teams, and interacting with sell-side research analysts. Through its fundamental research and analysis, the sub-adviser seeks to uncover one or more of the following five Value Buy Criteria that the sub-adviser believes may act as a catalyst for stock appreciation:•Resolvable Short-Term Problem – Companies that may have gone through a negative fundamental event that has had an impact on stock price and valuation, and the sub-adviser believes the company has a pathway to resolve the problem within a reasonable period of time.•Catalyst for Change – Companies that may have a material fundamental event going on that the sub-adviser believes the market is not pricing in to the valuation of the stock.•Unrecognized Assets – Companies that the sub-adviser believes may have some intrinsic value that the market is not appreciating and the sub-adviser believes there is a pathway to unlocking that value within the near to moderate term.•Fundamental Undervaluation – Companies that the sub-adviser believes lack significant sponsorship from the sell-side community and may have strong margins and growth but are in the 10-15% of the lowest valued names in a sector.•Take-Over Potential – Companies that the sub-adviser believes have assets that would be more attractive in the hands of other owners.The sub-adviser may sell a stock when the sub-adviser believes it has become fairly valued or when signs of fundamental deterioration appear. The sub-adviser may actively trade portfolio securities. Value stocks as a group may be out of favor and underperform the overall equity market for a long period of time, for example, while the market favors “growth” stocks.From time to time, the fund may invest up to 10% of its assets in exchange-traded funds (“ETFs”) in order to manage market liquidity and equitize cash. The fund may also invest some of its assets in cash or in money market instruments, including U.S. Government obligations and repurchase agreements, or make other short-term debt investments to maintain liquidity.1 “Russell®” and other service marks and trademarks related to the Russell indexes are trademarks of the London Stock Exchange Group companies.
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">Principal Risks:</span>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	Risk is inherent in all investing. Many factors and risks affect the fund's performance, including those described below. The value of your investment in the fund, as well as the amount of return you receive on your investment, may fluctuate significantly day to day and over time. You may lose part or all of your investment in the fund or your investment may not perform as well as other similar investments. The following is a summary description of principal risks (in alphabetical order after certain key risks) of investing in the fund. 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.You may lose money if you invest in this fund.Market – The market prices of the fund’s securities or other assets may go up or down, sometimes rapidly or unpredictably, due to general market conditions, overall economic trends or events, inflation, changes in interest rates, governmental actions or interventions, actions taken by the U.S. Federal Reserve or foreign central banks, market disruptions caused by tariffs, trade disputes or other factors, political developments, investor sentiment, the global and domestic effects of a pandemic, and other factors that may or may not be related to the issuer of the security or other asset. If the market prices of the fund’s securities and assets fall, the value of your investment will go down.Economies and financial markets throughout the world are increasingly interconnected. Economic, financial or political events, trading and tariff arrangements, public health events (such as the spread of infectious disease), wars, terrorism, cybersecurity events,technology and data interruptions, natural disasters, and other circumstances in one or more countries or regions could be highly disruptive to, and have profound impacts on, global economies or markets. As a result, whether or not the fund invests in securities of issuers located in or with significant exposure to the countries directly affected, the value and liquidity of the fund’s investments may go down.The pandemic of the novel coronavirus respiratory disease designated COVID-19 has resulted in extreme volatility in the financial markets, a domestic and global economic downturn, severe losses, particularly to some sectors of the economy and individual issuers, and reduced liquidity of many instruments.There also have been significant disruptions to business operations, including business closures; strained healthcare systems; disruptions to supply chains and employee availability; large fluctuations in consumer demand; and widespread uncertainty regarding the duration and long-term effects of the pandemic. The domestic and global economic downturn may be prolonged. The pandemic may result in domestic and foreign political and social instability, damage to diplomatic and international trade relations, and continued volatility and/or decreased liquidity in the securities markets. Developing or emerging market countries may be more impactedby the pandemic.The U.S. government and the Federal Reserve, as well as certain foreign governments and central banks, have taken extraordinary actions to support local and global economies and the financial markets in response to the COVID-19 pandemic, including by pushing interest rates to very low levels. This and other government intervention into the economy and financial markets to address the pandemic may not work as intended, particularly if the efforts are perceived by investors as being unlikely to achieve the desired results. Government actions to mitigate the economic impact of the pandemic have resulted in large expansion of government deficits and debt, the long-term consequences of which are not known. Rates of inflation have recently risen, which could adversely affect economies and markets.The COVID-19 pandemic could continue to adversely affect the value and liquidity of the fund’s investments, impair the fund’s ability to satisfy redemption requests, and negatively impact the fund’s performance. In addition, the pandemic, and measures taken to mitigate its effects, could result in disruptions to the services provided to the fund by its service providers.Value Investing – The prices of securities the sub-adviser believes are undervalued may not appreciate as anticipated or may go down. The value approach to investing involves the risk that stocks may remain undervalued, undervaluation may become more severe, or perceived undervaluation may actually represent intrinsic value. Value stocks as a group may be out of favor and underperform the overall equity market for a long period of time, for example, while the market favors “growth” stocks.Small Capitalization Companies – The fund will be exposed to additional risks as a result of its investments in the securities of small capitalization companies. Small capitalization companies may be more at risk than larger capitalization companies because, among other things, they may have limited product lines, operating history, market or financial resources, or because they may depend on limited management groups. Securities of small capitalization companies are generally more volatile than and may underperform larger capitalization companies, may be harder to sell at times and at prices the portfolio managers believe appropriate and may offer greater potential for losses.Equity Securities – Equity securities generally have greater risk of loss than debt securities. Stock markets are volatile and the value of equity securities may go up or down, sometimes rapidly and unpredictably. The value of equity securities fluctuates based on real or perceived changes in a company’s financial condition, factors affecting a particular industry or industries, and overall market, economic and political conditions. If the market prices of the equity securities owned by the fund fall, the value of your investment in the fund will decline. The fund may lose its entire investment in the equity securities of an issuer. A change in financial condition or other event affecting a single issuer may adversely impact securities markets as a whole.Liquidity – The fund may make investments that are illiquid or that become illiquid after purchase. Illiquid investments can be difficult to value, may trade at a discount from comparable, more liquid investments, and may be subject to wide fluctuations in value. If the fund is forced to sell an illiquid investment to meet redemption requests or other cash needs, the fund may be forced to sell at a substantial loss or may not be able to sell at all. Liquidity of particular investments, or even entire asset classes, including U.S. Treasury securities, can deteriorate rapidly, particularly during times of market turmoil, and those investments may be difficult or impossible for the fund to sell. This may prevent the fund from limiting losses.Valuation – The sales price the fund could receive for any particular portfolio investment may differ from the fund's valuation of the investment, particularly for securities that trade in thin or volatile markets, that are priced based upon valuations provided by third party pricing services that use matrix or evaluated pricing systems, or that are valued using a fair value methodology. These differences may increase significantly and affect fund investments more broadly during periods of market volatility. Investors who purchase or redeem fund shares on days when the fund is holding fair-valued securities may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the fund had not fair-valued securities or had used a different valuation methodology. The fund’s ability to value its investments may also be impacted by technological issues and/or errors by pricing services or other third party service providers.Management – The value of your investment may go down if the investment manager’s or sub-adviser's judgments and decisions are incorrect or otherwise do not produce the desired results, or if the investment strategy does not work as intended. You may also suffer losses if there are imperfections, errors or limitations in the quantitative, analytic or other tools, resources, information and data used, investment techniques applied, or the analyses employed or relied on, by the investment manager or sub-adviser, if such tools, resources, information or data are used incorrectly or otherwise do not work as intended, or if the investment manager’s or sub-adviser's investment style is out of favor or otherwise fails to produce the desired results. Any of these things could cause the fund to lose value or its results to lag relevant benchmarks or other funds with similar objectives.Active Trading – The fund may purchase and sell securities without regard to the length of time held. Active trading may be more pronounced during periods of market volatility, may have a negative impact on performance and may generate greater amounts of short-term capital gains.Large Shareholder – A significant portion of the fund’s shares may be owned by other funds sponsored by Transamerica. Transactions by these funds may be disruptive to the management of the fund. For example, the fund may experience large redemptions and could be required to sell securities at a time when it may not otherwise desire to do so. Such transactions may increase the fund’s brokerage and/or other transaction costs. These transactions may also accelerate the realization of taxable income to shareholders if such sales of investments resulted in gains. In addition, sizeable redemptions could cause the fund’s total expenses to increase.Underlying Exchange-Traded Funds – To the extent the fund invests its assets in underlying ETFs, its ability to achieve its investment objective will depend in part on the performance of the underlying ETFs in which it invests. Investing in underlying ETFs subjects the fund to the risks of investing in the underlying securities or assets held by those ETFs. Each of the underlying ETFs in which the fund may invest has its own investment risks, and those risks can affect the value of the underlying ETFs’ shares and therefore the value of the fund's investments. There can be no assurance that the investment objective of any underlying ETF will be achieved. In addition, the fund will bear a pro rata portion of the operating expenses of the underlying ETFs in which it invests.
Risk Lose Money [Text]	rr_RiskLoseMoney	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">You may lose money if you invest in this fund.</span>
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;">An investment in the fund is </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;margin-left:0%;">not a bank deposit and is not insured or guaranteed by the Federal </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Deposit Insurance Corporation or any other government agency.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">Performance:</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and the table below provide some indication of the risks of investing in the fund. The bar chart shows how the fund’s performance has varied from year to year. The table shows how the fund’s average annual total returns for different periods compare to the returns of a broad measure of market performance.As with all mutual funds, past performance (before and after taxes) is not a prediction of future results. Updated performance information is available on our website at www.transamerica.com/investments-fund-center or by calling 1-888-233-4339.Prior to November 1, 2018, the fund had a different sub-adviser and used different investment strategies. The performance set forth prior to that date is attributable to that previous sub-adviser.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> The bar chart and the table below provide some indication of the risks of investing in the fund. The bar chart shows how the fund’s performance has varied from year to year. The table shows how the fund’s average annual total returns for different periods compare to the returns of a broad measure of market performance.</span>
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	<span style="font-family:Times New Roman;font-size:10pt;">1-888-233-4339</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Times New Roman;font-size:10pt;">www.transamerica.com/investments</span><span style="font-family:Times New Roman;font-size:10pt;">-fund-center</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="font-family:Times New Roman;font-size:10pt;margin-left:0%;">As with all mutual funds, past performance (before and after taxes) </span><span style="font-family:Times New Roman;font-size:10pt;">is not a prediction of future results.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Times New Roman;font-size:8.5pt;font-weight:bold;margin-left:0%;">Annual Total Returns (calendar years ended December 31) - Class I2</span>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Quarter EndedReturnBest Quarter:12/31/202035.49%Worst Quarter:3/31/2020-38.33%
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Times New Roman;font-size:8.5pt;font-weight:bold;margin-left:0%;">Average Annual Total Returns (periods ended December 31, </span><span style="font-family:Times New Roman;font-size:8.5pt;font-weight:bold;line-height:11pt;"> </span><span style="font-family:Times New Roman;font-size:8.5pt;font-weight:bold;">2021)</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;margin-left:0%;">The after-tax returns are calculated using the historic highest individual</span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> federal marginal income tax rates and do not reflect the impact of state and local taxes.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> Actual after-tax returns may depend on the investor’s individual tax situation and may differ from those shown. After-tax returns may not be relevant if the investment is made through a tax-exempt or tax-deferred account, such as a 401(k) plan.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	Class I2 shares of the fund commenced operations on April 30, 2012. Performance information is shown for one year and from the date of the reorganization of certain funds into the fund (April 21, 2017). The applicable predecessor fund, whose accounting and performance history were adopted in the reorganizations, did not offer Class I2 shares.The after-tax returns are calculated using the historic highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns may depend on the investor’s individual tax situation and may differ from those shown. After-tax returns may not be relevant if the investment is made through a tax-exempt or tax-deferred account, such as a 401(k) plan.
Class I2 | Transamerica Small Cap Value | I2
Risk Return Abstract	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.76%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.04%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.80%
1 year	rr_ExpenseExampleYear01	$ 82
3 years	rr_ExpenseExampleYear03	255
5 years	rr_ExpenseExampleYear05	444
10 years	rr_ExpenseExampleYear10	$ 990
2018	rr_AnnualReturn2018	(18.69%)
2019	rr_AnnualReturn2019	21.05%
2020	rr_AnnualReturn2020	5.91%
2021	rr_AnnualReturn2021	27.98%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="color:#000000;font-family:Times New Roman;font-size:9pt;margin-left:0.0pt;">Best Quarter:</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	35.49%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="color:#000000;font-family:Times New Roman;font-size:9pt;margin-left:0.0pt;">Worst Quarter:</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(38.33%)
1 Year	rr_AverageAnnualReturnYear01	27.98%
Since Inception	rr_AverageAnnualReturnSinceInception	8.41%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 21, 2017
Class I2 | Transamerica Small Cap Value | Return After Taxes on Distributions | I2
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	8.11%
Since Inception	rr_AverageAnnualReturnSinceInception	3.59%
Class I2 | Transamerica Small Cap Value | Return After Taxes on Distributions and Sale of Fund Shares | I2
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	19.51%
Since Inception	rr_AverageAnnualReturnSinceInception	5.10%
Class I2 | Transamerica Small Cap Value | Russell 2000® Value Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.27%	[1]
Since Inception	rr_AverageAnnualReturnSinceInception	9.80%	[1]

[1] “Russell®” and other service marks and trademarks related to the Russell indexes are trademarks of the London Stock Exchange Group companies.