| N-2 - USD ($) | 3 Months Ended | 12 Months Ended | ||||||||
| Dec. 31, 2023 | Sep. 30, 2023 | Jun. 30, 2023 | Mar. 31, 2023 | Dec. 31, 2022 | Sep. 30, 2022 | Jun. 30, 2022 | Mar. 31, 2022 | Dec. 31, 2023 | ||
| Cover [Abstract] | ||||||||||
| Entity Central Index Key | 0001308335 | |||||||||
| Amendment Flag | false | |||||||||
| Document Type | N-CSR | |||||||||
| Entity Registrant Name | Eaton Vance Enhanced Equity Income Fund II | |||||||||
| Fee Table [Abstract] | ||||||||||
| Shareholder Transaction Expenses [Table Text Block] | Common shareholder transaction expenses Sales load paid by you (as a percentage of offering price) — 1 Offering expenses (as a percentage of offering price) None 2 Dividend reinvestment plan fees $5.00 3 1 If common shares are sold to or through underwriters, the Prospectus Supplement will set forth any applicable sales load. 2 Eaton Vance Management (“EVM”) will pay the expenses of the offering (other than the applicable commissions); therefore, offering expenses are not included in the Summary of Fund Expenses. Offering expenses generally include, but are not limited to, the preparation, review and filing with the SEC of the Fund’s registration statement (including its current Prospectus Supplement, the accompanying Prospectus and Statement of Additional Information (“SAI”)), the preparation, review and filing of any associated marketing or similar materials, costs associated with the printing, mailing or other distribution of its current Prospectus Supplement, the accompanying Prospectus, SAI and/or marketing materials, associated filing fees, stock exchange listing fees, and legal and auditing fees associated with the offering. 3 You will be charged a $5.00 service charge and pay brokerage charges if you direct the plan agent to sell your common shares held in a dividend reinvestment account. | |||||||||
| Sales Load [Percent] | [1] | |||||||||
| Dividend Reinvestment and Cash Purchase Fees | [2] | $ 5 | ||||||||
| Other Transaction Expenses [Abstract] | ||||||||||
| Other Transaction Expenses [Percent] | [3] | 0% | ||||||||
| Annual Expenses [Table Text Block] | Annual expenses Percentage of net assets 4 Investment adviser fee 1.00% 5 Other expenses 0.09 Total annual Fund oper ati 1.09% 4 Stated as a percentage of average net assets attributable to common shares for the year ended December 31, 2023. 5 The investment adviser fee paid by the Fund to EVM is based on the average daily gross assets of the Fund, including all assets attributable to any form of investment leverage that the Fund may utilize. Accordingly, if the Fund were to utilize investment leverage in the future, the investment adviser fee will increase as a percentage of net assets. | |||||||||
| Management Fees [Percent] | [4],[5] | 1% | ||||||||
| Other Annual Expenses [Abstract] | ||||||||||
| Other Annual Expenses [Percent] | [4] | 0.09% | ||||||||
| Total Annual Expenses [Percent] | [4] | 1.09% | ||||||||
| Expense Example [Table Text Block] | Example The following Example illustrates the expenses that common shareholders would pay on a $1,000 investment in common shares, assuming (i) total annual expenses of 1.09% of net assets attributable to common shares in years 1 through 10; (ii) a 5% annual return; and (iii) all distributions are reinvested at NAV: 1 Year 3 Years 5 Years 10 Years $11 $35 $60 $133 The above table and example and the assumption in the example of a 5% annual return are required by re g The example should not be considered a representation of past or future expenses, and the Fund’s actual expenses may be greater or less than those shown. Moreover, the Fund’s actual rate of return may be greater or less than the hypothetical 5% return shown in the example. | |||||||||
| Expense Example, Year 01 | $ 11 | |||||||||
| Expense Example, Years 1 to 3 | 35 | |||||||||
| Expense Example, Years 1 to 5 | 60 | |||||||||
| Expense Example, Years 1 to 10 | $ 133 | |||||||||
| Purpose of Fee Table , Note [Text Block] | The purpose of the table below is to help you understand all fees and expenses that you, as a holder of common shares, would bear directly or indirectly. The table shows Fund expenses as a percentage of net assets attributable to common shares for the year ended December 31, 2023. | |||||||||
| Basis of Transaction Fees, Note [Text Block] | as a percentage of offering price | |||||||||
| Other Transaction Fees, Note [Text Block] | Eaton Vance Management (“EVM”) will pay the expenses of the offering (other than the applicable commissions); therefore, offering expenses are not included in the Summary of Fund Expenses. Offering expenses generally include, but are not limited to, the preparation, review and filing with the SEC of the Fund’s registration statement (including its current Prospectus Supplement, the accompanying Prospectus and Statement of Additional Information (“SAI”)), the preparation, review and filing of any associated marketing or similar materials, costs associated with the printing, mailing or other distribution of its current Prospectus Supplement, the accompanying Prospectus, SAI and/or marketing materials, associated filing fees, stock exchange listing fees, and legal and auditing fees associated with the offering. | |||||||||
| Management Fee not based on Net Assets, Note [Text Block] | The investment adviser fee paid by the Fund to EVM is based on the average daily gross assets of the Fund, including all assets attributable to any form of investment leverage that the Fund may utilize. Accordingly, if the Fund were to utilize investment leverage in the future, the investment adviser fee will increase as a percentage of net assets. | |||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Investment Objectives and Practices [Text Block] | Investment Objectives. The Fund’s primary investment objective is to provide current income, with a secondary objective of capital appreciation. Principal Strategies. The Fund pursues its investment objectives by investing primarily in a portfolio of mid-and large-capitalization common stocks. Under normal market conditions, the Fund seeks to generate current earnings from option premiums by selling covered call options on a substantial portion of its portfolio securities. Under normal market conditions, the Fund invests at least 80% of its total assets in common stocks. For the purposes of the 80% test, total assets is defined as net assets plus any borrowings for investment purposes. The Fund generally invests in common stocks on which exchange traded call options are currently available. The Fund invests primarily in common stocks of U.S. issuers, although the Fund may invest up to 25% of its total assets in securities of foreign issuers, including American Depositary Receipts (‘‘ADRs’’), Global Depositary Receipts (‘‘GDRs’’) and European Depositary Receipts (‘‘EDRs’’). Under normal market conditions, the Fund pursues its primary investment objective principally by employing an options strategy of writing (selling) covered call options on a substantial portion of its portfolio securities, although on up to 5% of the Fund’s net assets, the Fund may sell the stock underlying a call option prior to purchasing back the call option. Such sales shall occur no more than three days before the option buy back. The extent of option writing activity will depend upon market conditions and the Adviser’s ongoing assessment of the attractiveness of writing call options on the Fund’s stock holdings. Writing call options involves a tradeoff between the option premiums received and reduced participation in potential future stock price appreciation. Depending on the Adviser’s evaluation, the Fund may write call options on varying percentages of the Fund’s common stock holdings. The Fund seeks to generate current earnings from option writing premiums and, to a lesser extent, from dividends on stocks held. In addition to the strategy of selling covered call options, the Fund may invest up to 20% of its total assets in other derivative instruments acquired for hedging, risk management and investment purposes, provided that no more than 10% of the Fund’s total assets may be invested in such derivative instruments acquired for non-hedging purposes. Among other derivative strategies, the Fund may purchase put options on the S&P 500® and other broad-based securities indices deemed suitable for this purpose, and/or on individual stocks held in its portfolio or use other derivative instruments in order to help protect against a decline in the value of its portfolio securities. Derivative instruments may be used by the Fund to enhance returns or as a substitute for the purchase or sale of securities. | |||||||||
| Risk Factors [Table Text Block] | Principal Risks Market Discount Risk. As with any security, the market value of the common shares may increase or decrease from the amount initially paid for the common shares. The Fund’s common shares have traded both at a premium and at a discount relative to NAV. The shares of closed-end management investment companies frequently trade at a discount from their NAV. This is a risk separate and distinct from the risk that the Fund’s NAV may decrease. Investment and Market Risk. An investment in common shares is subject to investment risk, including the possible loss of the entire principal amount invested. An investment in common shares represents an indirect investment in the securities owned by the Fund, which are generally traded on a securities exchange or in the over-the-counter markets. The value of these securities, like other market investments, may move up or down, sometimes rapidly and unpredictably. In addition, by writing (selling) call options on the equity securities held in the Fund’s portfolio, the capital appreciation potential of such securities will be limited to the difference between the exercise price of the call options written and the purchase price of the equity security underlying such options. The common shares at any point in time may be worth less than the original investment, even after taking into account any reinvestment of distributions. The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility. No active trading market may exist for certain investments held by the Fund, which may impair the ability of the Fund to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets. Issuer Risk. The value of securities held by the Fund may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services. Equity Securities Risk. The value of equity securities and related instruments may decline in response to adverse changes in the economy or the economic outlook; deterioration in investor sentiment; interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer and sector-specific considerations; unexpected trading activity among retail investors; or other factors. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines in value, the value of the Fund’s equity securities will also likely decline. Although prices can rebound, there is no assurance that values will return to previous levels. Option Strategy Risk. As the writer of a call option, the Fund forgoes, during the option’s life, the opportunity to profit from increases in the market value of the security covering the call option above the sum of the option premium received and the exercise price of the call, but has retained the risk of loss, minus the option premium received, should the price of the underlying security decline. The writer of an option has no control over when during the exercise period of the option it may be required to fulfill its obligation as a writer of the option. Once an option writer has received an exercise notice, it cannot effect a closing purchase transaction in order to terminate its obligation under the option and must deliver the underlying security at the exercise price. Thus, the use of options may require the Fund to sell portfolio securities at inopportune times or for prices other than current market values, will limit the amount of appreciation the Fund can realize on an investment, or may cause the Fund to hold a security that it might otherwise sell. The value of options may also be adversely affected if the market for such options becomes less liquid or smaller. Derivatives Risk. The Fund’s exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative (“reference instrument”), due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create leverage in the Fund, which represents a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative’s counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in (or be unable to achieve) the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment. A derivative investment also involves the risks relating to the reference instrument underlying the investment. Risks of Investing in Smaller and Mid-Sized Companies. The Fund may make investments in stocks of companies whose market capitalization is considered middle sized or “mid-cap.” Smaller and mid-sized companies often are newer or less established companies than larger companies. Investments in smaller and mid-sized companies carry additional risks because earnings of these companies tend to be less predictable; they often have limited product lines, markets, distribution channels or financial resources; and the management of such companies may be dependent upon one or a few key people. The market movements of equity securities of smaller and mid-sized companies may be more abrupt or erratic than the market movements of equity securities of larger, more established companies or the stock market in general. Historically, smaller and mid-sized companies have sometimes gone through extended periods when they did not perform as well as larger companies. In addition, equity securities of smaller and mid-sized companies generally are less liquid than those of larger companies. This means that the Fund could have greater difficulty selling such securities at the time and price that the Fund would like. Risks of Growth Stock Investing. The Fund invests substantially in stocks with “growth” characteristics. Growth stocks can react differently to issuer, political, market, and economic developments than the market as a whole and other types of stocks. Growth stocks tend to be more expensive relative to their earnings or assets compared to other types of stocks. As a result, growth stocks tend to be sensitive to changes in their earnings and more volatile than other types of stocks. Foreign Investment Risk. Foreign investments can be adversely affected by political, economic and market developments abroad, including the imposition of economic and other sanctions by the United States or another country against a particular country or countries, organizations, entities and/or individuals. There may be less publicly available information about foreign issuers because they may not be subject to reporting practices, requirements or regulations comparable to those to which United States companies are subject. Adverse changes in investment regulations, capital requirements or exchange controls could adversely affect the value of the Fund’s investments. Foreign markets may be smaller, less liquid and more volatile than the major markets in the United States, and as a result, Fund share values may be more volatile. Trading in foreign markets typically involves higher expense than trading in the United States. The Fund may have difficulties enforcing its legal or contractual rights in a foreign country. Depository receipts are subject to many of the risks associated with investing directly in foreign instruments. Emerging Markets Investment Risk. Investment markets within emerging market countries are typically smaller, less liquid, less developed and more volatile than those in more developed markets like the United States, and may be focused in certain sectors. Emerging market securities often involve greater risks than developed market securities. The information available about an emerging market issuer may be less reliable than for comparable issuers in more developed capital markets. Currency Risk. Exchange rates for currencies fluctuate daily. The value of foreign investments may be affected favorably or unfavorably by changes in currency exchange rates in relation to the U.S. dollar. Currency markets generally are not as regulated as securities markets and currency transactions are subject to settlement, custodial and other operational risks. Interest Rate Risk. The level of premiums from call options writing and the amounts available for distribution from the Fund’s options activity may decrease in declining interest rate environments. Any preferred stocks paying fixed dividend rates in which the Fund invests, will likely change in value as market interest rates change. When interest rates rise, the market value of such securities generally will fall. To the extent that the Fund invests in preferred stocks, the net asset value and price of the common shares may decline if market interest rates rise. Interest rates are currently low relative to historic levels. During periods of declining interest rates, an issuer of preferred stock may exercise its option to redeem securities prior to maturity, forcing the Fund to reinvest in lower yielding securities. This is known as call risk. During periods of rising interest rates, the average life of certain types of securities may be extended because of slower than expected payments. This may lock in a below market yield, increase the security’s duration, and reduce the value of the security. This is known as extension risk. The value of the Fund’s common stock investments may also be influenced by changes in interest rates. Sector Risk. Because the Fund may, under certain marke t co Liquidity Risk. The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices. Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress. Inflation Risk. Inflation risk is the risk that the purchasing power of assets or income from investment will be worth less in the future as inflation decreases the value of money. As inflation increases, the real value of the common shares and distributions thereon can decline. Financial Leverage Risk . Although the Fund has no current intention to do so, the Fund is authorized to utilize leverage through the issuance of preferred shares and/or borrowings, including the issuance of debt securities. In the event that the Fund determines in the future to utilize investment leverage, there can be no assurance that such a leveraging strategy will be successful during any period in which it is employed. Leverage creates risks for common shareholders, including the likelihood of greater volatility of net asset value and market price of the common shares and the risk that fluctuations in distribution rates on any preferred shares or fluctuations in borrowing costs may affect the return to common shareholders. To the extent the income derived from securities purchased with proceeds received from leverage exceeds the cost of leverage, the Fund’s distributions will be greater than if leverage had not been used. Conversely, if the income from the securities purchased with such proceeds is not sufficient to cover the cost of leverage, the amount available for distribution to common shareholders will be less than if leverage had not been used. In the latter case, Eaton Vance, in its best judgment, may nevertheless determine to maintain the Fund’s leveraged position if it deems such action to be appropriate. The costs of an offering of preferred shares and/or a borrowing program would be borne by common shareholders and consequently would result in a reduction of the net asset value of common shares. In addition, the fee paid to Eaton Vance will be calculated on the basis of the Fund’s average daily gross assets, including proceeds from the issuance of preferred shares and/or borrowings, so the fees will be higher when leverage is utilized. In this regard, holders of preferred shares do not bear the investment advisory fee. Rather, common shareholders bear the portion of the investment advisory fee attributable to the assets purchased with the proceeds of the preferred shares offering. Risks Associated with Active Management. The success of the Fund’s investment strategy depends on portfolio management’s successful application of analytical skills and investment judgment. Active management involves subjective decisions and there is no guarantee that such decisions will produce the desired results or expected returns. Recent Market Conditions. The outbreak of COVID-19 and efforts to contain its spread have resulted in closing borders, enhanced health screenings, changes to healthcare service preparation and delivery, quarantines, cancellations, disruptions to supply chains and customer activity, as well as general concern and uncertainty. The impact of this coronavirus and the effects of other infectious illness outbreaks, epidemics or pandemics, may be short term or may continue for an extended period of time. Health crises caused by outbreaks of disease, such as the coronavirus outbreak, may exacerbate other pre-existing political, social and economic risks and disrupt normal market conditions and operations. For example, a global pandemic or other widespread health crisis could cause substantial market volatility and exchange trading suspensions and closures. In addition, the increasing interconnectedness of markets around the world may result in many markets being affected by events or conditions in a single country or region or events affecting a single or small number of issuers. The coronavirus outbreak and public and private sector responses thereto have led to large portions of the populations of many countries working from home for indefinite periods of time, temporary or permanent layoffs, disruptions in supply chains, and lack of availability of certain goods. The impact of such responses could adversely affect the information technology and operational systems upon which the Fund and the Fund’s service providers rely, and could otherwise disrupt the ability of the employees of the Fund’s service providers to perform critical tasks relating to the Fund. Any such impact could adversely affect the Fund’s performance, or the performance of the securities in which the Fund invests and may lead to losses on your investment in the Fund. Cybersecurity Risk. With the increased use of technologies by Fund service providers to conduct business, such as the Internet, the Fund is susceptible to operational, information security and related risks. In general, cyber incidents can result from deliberate attacks or unintentional events. Cybersecurity failures by or breaches of the Fund’s investment adviser or administrator and other service providers (including, but not limited to, the custodian or transfer agent), and the issuers of securities in which the Fund invests, may disrupt and otherwise adversely affect their business operations. This may result in financial losses to the Fund, impede Fund trading, interfere with the Fund’s ability to calculate its net asset value, interfere with Fund shareholders’ ability to transact business or cause violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, or additional compliance costs. Market Disruption . Global instability, war, geopolitical tensions and terrorist attacks in the United States and around the world have previously resulted, and may in the future result in market volatility and may have long-term effects on the United States and worldwide financial markets and may cause further economic uncertainties in the United States and worldwide. The Fund cannot predict the effects of significant future events on the global economy and securities markets. A similar disruption of the financial markets could impact interest rates, auctions, secondary trading, ratings, credit risk, inflation and other factors relating to the common shares. Anti-Takeover Provisions. The Fund’s Agreement and Declaration of Trust (the “Declaration of Trust”) and Amended and Restated By-Laws include provisions that could have the effect of limiting the ability of other persons or entities to acquire control of the Fund or to change the composition of its Board. For example, pursuant to the Fund’s Declaration of Trust, the Fund Board is divided into three classes of Trustees with each class serving for a three-year term and certain types of transactions require the favorable vote of holders of at least 75% of the outstanding shares of the Fund. General Fund Investing Risks. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objectives. It is possible to lose money by investing in the Fund. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. | |||||||||
| Share Price [Table Text Block] | The following table sets forth for each of the periods indicated the high and low closing market prices for the common shares on the New York Stock Exchange, and the corresponding NAV per share and the premium or discount to NAV per share at which the Fund’s common shares were trading as of such date. Market Price ($) NAV per Share on NAV Premium/(Discount) on Fiscal Quarter Ended High Low High Low High Low December 31, 2023 18.72 15.91 19.71 17.17 (5.02) (7.34) September 30, 2023 18.65 16.96 19.18 17.67 (2.76) (4.02) June 30, 2023 17.89 15.96 18.61 16.77 (3.87) (4.83) March 31, 2023 17.81 15.43 17.25 15.88 3.25 (2.83) December 31, 2022 17.56 15.44 16.86 15.60 4.15 (1.03) September 30, 2022 19.60 15.30 18.84 15.45 4.03 (0.97) June 30, 2022 21.29 15.61 21.08 16.05 1.00 (2.74) March 31, 2022 24.38 19.30 23.84 19.06 2.27 1.26 | |||||||||
| Market Discount Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Market Discount Risk. As with any security, the market value of the common shares may increase or decrease from the amount initially paid for the common shares. The Fund’s common shares have traded both at a premium and at a discount relative to NAV. The shares of closed-end management investment companies frequently trade at a discount from their NAV. This is a risk separate and distinct from the risk that the Fund’s NAV may decrease. | |||||||||
| Investment and Market Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Investment and Market Risk. An investment in common shares is subject to investment risk, including the possible loss of the entire principal amount invested. An investment in common shares represents an indirect investment in the securities owned by the Fund, which are generally traded on a securities exchange or in the over-the-counter markets. The value of these securities, like other market investments, may move up or down, sometimes rapidly and unpredictably. In addition, by writing (selling) call options on the equity securities held in the Fund’s portfolio, the capital appreciation potential of such securities will be limited to the difference between the exercise price of the call options written and the purchase price of the equity security underlying such options. The common shares at any point in time may be worth less than the original investment, even after taking into account any reinvestment of distributions. The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility. No active trading market may exist for certain investments held by the Fund, which may impair the ability of the Fund to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets. | |||||||||
| Issuer Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Issuer Risk. The value of securities held by the Fund may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services. | |||||||||
| Equity Securities Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Equity Securities Risk. The value of equity securities and related instruments may decline in response to adverse changes in the economy or the economic outlook; deterioration in investor sentiment; interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer and sector-specific considerations; unexpected trading activity among retail investors; or other factors. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines in value, the value of the Fund’s equity securities will also likely decline. Although prices can rebound, there is no assurance that values will return to previous levels. | |||||||||
| Option Strategy Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Option Strategy Risk. As the writer of a call option, the Fund forgoes, during the option’s life, the opportunity to profit from increases in the market value of the security covering the call option above the sum of the option premium received and the exercise price of the call, but has retained the risk of loss, minus the option premium received, should the price of the underlying security decline. The writer of an option has no control over when during the exercise period of the option it may be required to fulfill its obligation as a writer of the option. Once an option writer has received an exercise notice, it cannot effect a closing purchase transaction in order to terminate its obligation under the option and must deliver the underlying security at the exercise price. Thus, the use of options may require the Fund to sell portfolio securities at inopportune times or for prices other than current market values, will limit the amount of appreciation the Fund can realize on an investment, or may cause the Fund to hold a security that it might otherwise sell. The value of options may also be adversely affected if the market for such options becomes less liquid or smaller. | |||||||||
| Derivatives Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Derivatives Risk. The Fund’s exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative (“reference instrument”), due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create leverage in the Fund, which represents a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative’s counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in (or be unable to achieve) the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment. A derivative investment also involves the risks relating to the reference instrument underlying the investment. | |||||||||
| Risks of Investing in Smaller and MidSized Companies [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Risks of Investing in Smaller and Mid-Sized Companies. The Fund may make investments in stocks of companies whose market capitalization is considered middle sized or “mid-cap.” Smaller and mid-sized companies often are newer or less established companies than larger companies. Investments in smaller and mid-sized companies carry additional risks because earnings of these companies tend to be less predictable; they often have limited product lines, markets, distribution channels or financial resources; and the management of such companies may be dependent upon one or a few key people. The market movements of equity securities of smaller and mid-sized companies may be more abrupt or erratic than the market movements of equity securities of larger, more established companies or the stock market in general. Historically, smaller and mid-sized companies have sometimes gone through extended periods when they did not perform as well as larger companies. In addition, equity securities of smaller and mid-sized companies generally are less liquid than those of larger companies. This means that the Fund could have greater difficulty selling such securities at the time and price that the Fund would like. | |||||||||
| Risks of Growth Stock Investing [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Risks of Growth Stock Investing. The Fund invests substantially in stocks with “growth” characteristics. Growth stocks can react differently to issuer, political, market, and economic developments than the market as a whole and other types of stocks. Growth stocks tend to be more expensive relative to their earnings or assets compared to other types of stocks. As a result, growth stocks tend to be sensitive to changes in their earnings and more volatile than other types of stocks. | |||||||||
| Foreign Investment Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Foreign Investment Risk. Foreign investments can be adversely affected by political, economic and market developments abroad, including the imposition of economic and other sanctions by the United States or another country against a particular country or countries, organizations, entities and/or individuals. There may be less publicly available information about foreign issuers because they may not be subject to reporting practices, requirements or regulations comparable to those to which United States companies are subject. Adverse changes in investment regulations, capital requirements or exchange controls could adversely affect the value of the Fund’s investments. Foreign markets may be smaller, less liquid and more volatile than the major markets in the United States, and as a result, Fund share values may be more volatile. Trading in foreign markets typically involves higher expense than trading in the United States. The Fund may have difficulties enforcing its legal or contractual rights in a foreign country. Depository receipts are subject to many of the risks associated with investing directly in foreign instruments. | |||||||||
| Emerging Markets Investment Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Emerging Markets Investment Risk. Investment markets within emerging market countries are typically smaller, less liquid, less developed and more volatile than those in more developed markets like the United States, and may be focused in certain sectors. Emerging market securities often involve greater risks than developed market securities. The information available about an emerging market issuer may be less reliable than for comparable issuers in more developed capital markets. | |||||||||
| Currency Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Currency Risk. Exchange rates for currencies fluctuate daily. The value of foreign investments may be affected favorably or unfavorably by changes in currency exchange rates in relation to the U.S. dollar. Currency markets generally are not as regulated as securities markets and currency transactions are subject to settlement, custodial and other operational risks. | |||||||||
| Sector Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Sector Risk. Because the Fund may, under certain marke t co | |||||||||
| Liquidity Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Liquidity Risk. The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices. Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress. | |||||||||
| Inflation Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Inflation Risk. Inflation risk is the risk that the purchasing power of assets or income from investment will be worth less in the future as inflation decreases the value of money. As inflation increases, the real value of the common shares and distributions thereon can decline. | |||||||||
| Financial Leverage Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Financial Leverage Risk . Although the Fund has no current intention to do so, the Fund is authorized to utilize leverage through the issuance of preferred shares and/or borrowings, including the issuance of debt securities. In the event that the Fund determines in the future to utilize investment leverage, there can be no assurance that such a leveraging strategy will be successful during any period in which it is employed. Leverage creates risks for common shareholders, including the likelihood of greater volatility of net asset value and market price of the common shares and the risk that fluctuations in distribution rates on any preferred shares or fluctuations in borrowing costs may affect the return to common shareholders. To the extent the income derived from securities purchased with proceeds received from leverage exceeds the cost of leverage, the Fund’s distributions will be greater than if leverage had not been used. Conversely, if the income from the securities purchased with such proceeds is not sufficient to cover the cost of leverage, the amount available for distribution to common shareholders will be less than if leverage had not been used. In the latter case, Eaton Vance, in its best judgment, may nevertheless determine to maintain the Fund’s leveraged position if it deems such action to be appropriate. The costs of an offering of preferred shares and/or a borrowing program would be borne by common shareholders and consequently would result in a reduction of the net asset value of common shares. In addition, the fee paid to Eaton Vance will be calculated on the basis of the Fund’s average daily gross assets, including proceeds from the issuance of preferred shares and/or borrowings, so the fees will be higher when leverage is utilized. In this regard, holders of preferred shares do not bear the investment advisory fee. Rather, common shareholders bear the portion of the investment advisory fee attributable to the assets purchased with the proceeds of the preferred shares offering. | |||||||||
| Risks Associated with Active Management [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Risks Associated with Active Management. The success of the Fund’s investment strategy depends on portfolio management’s successful application of analytical skills and investment judgment. Active management involves subjective decisions and there is no guarantee that such decisions will produce the desired results or expected returns. | |||||||||
| Recent Market Conditions [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Recent Market Conditions. The outbreak of COVID-19 and efforts to contain its spread have resulted in closing borders, enhanced health screenings, changes to healthcare service preparation and delivery, quarantines, cancellations, disruptions to supply chains and customer activity, as well as general concern and uncertainty. The impact of this coronavirus and the effects of other infectious illness outbreaks, epidemics or pandemics, may be short term or may continue for an extended period of time. Health crises caused by outbreaks of disease, such as the coronavirus outbreak, may exacerbate other pre-existing political, social and economic risks and disrupt normal market conditions and operations. For example, a global pandemic or other widespread health crisis could cause substantial market volatility and exchange trading suspensions and closures. In addition, the increasing interconnectedness of markets around the world may result in many markets being affected by events or conditions in a single country or region or events affecting a single or small number of issuers. The coronavirus outbreak and public and private sector responses thereto have led to large portions of the populations of many countries working from home for indefinite periods of time, temporary or permanent layoffs, disruptions in supply chains, and lack of availability of certain goods. The impact of such responses could adversely affect the information technology and operational systems upon which the Fund and the Fund’s service providers rely, and could otherwise disrupt the ability of the employees of the Fund’s service providers to perform critical tasks relating to the Fund. Any such impact could adversely affect the Fund’s performance, or the performance of the securities in which the Fund invests and may lead to losses on your investment in the Fund. | |||||||||
| Cybersecurity Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Cybersecurity Risk. With the increased use of technologies by Fund service providers to conduct business, such as the Internet, the Fund is susceptible to operational, information security and related risks. In general, cyber incidents can result from deliberate attacks or unintentional events. Cybersecurity failures by or breaches of the Fund’s investment adviser or administrator and other service providers (including, but not limited to, the custodian or transfer agent), and the issuers of securities in which the Fund invests, may disrupt and otherwise adversely affect their business operations. This may result in financial losses to the Fund, impede Fund trading, interfere with the Fund’s ability to calculate its net asset value, interfere with Fund shareholders’ ability to transact business or cause violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, or additional compliance costs. | |||||||||
| Market Disruption [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Market Disruption . Global instability, war, geopolitical tensions and terrorist attacks in the United States and around the world have previously resulted, and may in the future result in market volatility and may have long-term effects on the United States and worldwide financial markets and may cause further economic uncertainties in the United States and worldwide. The Fund cannot predict the effects of significant future events on the global economy and securities markets. A similar disruption of the financial markets could impact interest rates, auctions, secondary trading, ratings, credit risk, inflation and other factors relating to the common shares. | |||||||||
| Anti Takeover Provisions [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Anti-Takeover Provisions. The Fund’s Agreement and Declaration of Trust (the “Declaration of Trust”) and Amended and Restated By-Laws include provisions that could have the effect of limiting the ability of other persons or entities to acquire control of the Fund or to change the composition of its Board. For example, pursuant to the Fund’s Declaration of Trust, the Fund Board is divided into three classes of Trustees with each class serving for a three-year term and certain types of transactions require the favorable vote of holders of at least 75% of the outstanding shares of the Fund. | |||||||||
| General Fund Investing Risks [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | General Fund Investing Risks. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objectives. It is possible to lose money by investing in the Fund. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. | |||||||||
| Interest Rate Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Interest Rate Risk. The level of premiums from call options writing and the amounts available for distribution from the Fund’s options activity may decrease in declining interest rate environments. Any preferred stocks paying fixed dividend rates in which the Fund invests, will likely change in value as market interest rates change. When interest rates rise, the market value of such securities generally will fall. To the extent that the Fund invests in preferred stocks, the net asset value and price of the common shares may decline if market interest rates rise. Interest rates are currently low relative to historic levels. During periods of declining interest rates, an issuer of preferred stock may exercise its option to redeem securities prior to maturity, forcing the Fund to reinvest in lower yielding securities. This is known as call risk. During periods of rising interest rates, the average life of certain types of securities may be extended because of slower than expected payments. This may lock in a below market yield, increase the security’s duration, and reduce the value of the security. This is known as extension risk. The value of the Fund’s common stock investments may also be influenced by changes in interest rates. | |||||||||
| Common Shares [Member] | ||||||||||
| Other Annual Expenses [Abstract] | ||||||||||
| Basis of Transaction Fees, Note [Text Block] | Percentage of net assets | |||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Lowest Price or Bid | $ 15.91 | $ 16.96 | $ 15.96 | $ 15.43 | $ 15.44 | $ 15.3 | $ 15.61 | $ 19.3 | ||
| Highest Price or Bid | 18.72 | 18.65 | 17.89 | 17.81 | 17.56 | 19.6 | 21.29 | 24.38 | ||
| Lowest Price or Bid, NAV | 17.17 | 17.67 | 16.77 | 15.88 | 15.6 | 15.45 | 16.05 | 19.06 | ||
| Highest Price or Bid, NAV | $ 19.71 | $ 19.18 | $ 18.61 | $ 17.25 | $ 16.86 | $ 18.84 | $ 21.08 | $ 23.84 | ||
| Highest Price or Bid, Premium (Discount) to NAV [Percent] | (5.02%) | (2.76%) | (3.87%) | 3.25% | 4.15% | 4.03% | 1% | 2.27% | ||
| Lowest Price or Bid, Premium (Discount) to NAV [Percent] | (7.34%) | (4.02%) | (4.83%) | (2.83%) | (1.03%) | (0.97%) | (2.74%) | 1.26% | ||
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | ||||||||||
| Outstanding Security, Title [Text Block] | Common Shares | |||||||||
| Outstanding Security, Held [Shares] | 52,307,415 | |||||||||
| [1]If common shares are sold to or through underwriters, the Prospectus Supplement will set forth any applicable sales load.[2]You will be charged a $5.00 service charge and pay brokerage charges if you direct the plan agent to sell your common shares held in a dividend reinvestment account.[3]Eaton Vance Management (“EVM”) will pay the expenses of the offering (other than the applicable commissions); therefore, offering expenses are not included in the Summary of Fund Expenses. Offering expenses generally include, but are not limited to, the preparation, review and filing with the SEC of the Fund’s registration statement (including its current Prospectus Supplement, the accompanying Prospectus and Statement of Additional Information (“SAI”)), the preparation, review and filing of any associated marketing or similar materials, costs associated with the printing, mailing or other distribution of its current Prospectus Supplement, the accompanying Prospectus, SAI and/or marketing materials, associated filing fees, stock exchange listing fees, and legal and auditing fees associated with the offering.[4]Stated as a percentage of average net assets attributable to common shares for the year ended December 31, 2023.[5]The investment adviser fee paid by the Fund to EVM is based on the average daily gross assets of the Fund, including all assets attributable to any form of investment leverage that the Fund may utilize. Accordingly, if the Fund were to utilize investment leverage in the future, the investment adviser fee will increase as a percentage of net assets. | ||||||||||
