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	$5.00³

¹If common shares are sold to or through underwriters, the Prospectus Supplement will set forth any applicable sales load.

²Eaton 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.

³You 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]

$ 5.00

Other Transaction Expenses [Abstract]

Other Transaction Expenses [Percent]

^[3]

0.00%

Annual Expenses [Table Text Block]

Annual expenses	Percentage of net assets attributable to common shares⁴
Investment adviser fee	1.00%⁵
Other expenses	0.07%
Total annual Fund operating expenses	1.07%

⁴Stated as a percentage of average net assets attributable to common shares for the year ended October 31, 2022.

⁵The 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]

1.00%

Other Annual Expenses [Abstract]

Other Annual Expenses [Percent]

^[4]

0.07%

Total Annual Expenses [Percent]

^[4]

1.07%

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 1.07% 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	$34	$59	$131

The above table and example and the assumption in the example of a 5% annual return are required by regulations of the U.S. Securities and Exchange Commission (“SEC”) that are applicable to all investment companies; the assumed 5% annual return is not a prediction of, and does not represent, the projected or actual performance of the Fund’s common shares. In addition, while the example assumes reinvestment of all dividends and distributions at NAV, participants in the Fund’s dividend reinvestment plan may receive common shares purchased or issued at a price or value different from NAV. The example does not include sales load or estimated offering costs, which would cause the expenses shown in the example to increase.

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

Expense Example, Years 1 to 5

Expense Example, Years 1 to 10

$ 131

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 common shareholder, would bear directly or indirectly. The table shows Fund expenses stated as a percentage of net assets attributable to common shares, and not as a percentage of total assets.

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 and gains, with a secondary objective of capital appreciation.

Principal Strategies. Under normal market conditions, the Fund’s investment program consists of owning a diversified portfolio of common stocks. The Fund seeks to earn high levels of tax-advantaged income and gains by (1) investing in stocks that pay dividends that qualify for favorable federal income tax treatment and/or (2) writing (selling) stock index call options with respect to a portion of its common stock portfolio value.

Under normal market conditions, the Fund invests at least 80% of its total assets in a combination of (1) dividend-paying common stocks and (2) common stocks the value of which is subject to covered written index call options.

Typically, the Fund invests in common stocks of United States issuers. The Fund may invest up to 40% of its total assets in securities of foreign issuers, including securities evidenced by American Depositary Receipts (“ADRs”), Global Depositary Receipts (“GDRs”) and European Depositary Receipts (“EDRs”). The Fund may invest up to 5% of its total assets in securities of emerging market issuers. The Fund expects that its assets will normally be invested across a broad range of industries and market sectors. The Fund may not invest 25% or more of its total assets in the securities of issuers in any single industry. The Fund may invest a portion of its assets in stocks of mid-capitalization companies.

The Fund writes call options on one or more broad-based stock indices that the Adviser believes collectively approximate the characteristics of its common stock portfolio (or that portion of its portfolio against which options are written) and that present attractive opportunities to earn options premiums. The Fund writes call options on the S&P 500® Index (the “S&P 500®”), and may also write call options on other domestic and foreign stock indices. Over time, the indices on which the Fund writes call options may vary as a result of changes in the availability and liquidity of various listed index options, changes in stock portfolio holdings, the Adviser’s evaluation of equity market conditions and other factors. Writing index call options involves a tradeoff between the option premiums received and reduced participation in potential future stock price appreciation.

The Fund may consider investments in stocks that pay dividends that qualify for federal income taxation at rates applicable to long-term capital gains, and may seek to enhance the level of tax-advantaged dividend income it receives by engaging in dividend capture trading. In a dividend capture trade, the Fund sells a stock on or shortly after the stock’s ex-dividend date and uses the sale proceeds to purchase one or more other stocks that are expected to pay dividends before the next dividend payment on the stock being sold. Through this practice, the Fund may receive more dividend payments over a given time period than if it held a single stock. By complying with applicable holding period and other requirements while engaging in dividend capture trading, the Fund may enhance the level of tax-advantaged dividend income it receives. The use of dividend capture trading strategies will expose the Fund to increased trading costs and potentially higher short-term gain or loss. The Fund may use derivatives to manage exposure to certain sectors and/or markets in connection with its use of dividend capture trading. The Fund may buy and sell equity index futures contracts for this purpose, but may also engage in other types of derivatives to manage such exposures.

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.

Market Risk. 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. 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.

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. The Fund’s option strategy seeks to take advantage of, and its effectiveness is dependent on, a general excess of option price-implied volatilities for the S&P 500® over realized index volatilities. This market observation is often attributed to an excess of natural buyers over natural sellers of S&P 500® index options. There can be no assurance that this imbalance will apply in the future over specific periods or generally. It is possible that the imbalance could decrease or be eliminated by actions of investors, including the Fund, that employ strategies seeking to take advantage of the imbalance, which could have an adverse effect on the Fund’s ability to achieve its investment objective.

Risk of Selling Index Call Options. The purchaser of an index call option has the right to any appreciation in the value of the index over the exercise price of the call option as of the valuation date of the option. Because their exercise is settled in cash, sellers of index call options such as the Fund cannot provide in advance for their potential settlement obligations by acquiring and holding the underlying securities. The Fund intends to mitigate the risks of its options activities by holding a diversified portfolio of stocks that the Fund’s investment adviser believes collectively approximate the characteristics of the indices on which options are written. The Fund will not, however, hold stocks that fully replicate the indices on which it writes call options. Due to tax considerations, the Fund intends to limit the overlap between its stock holdings (and any subset thereof) and each index on which it has outstanding options positions to less than 70% on an ongoing basis. The Fund’s stock holdings will normally include stocks not included in the indices on which it writes call options. Consequently, the Fund bears the risk that the performance of its stock portfolio will vary from the performance of the indices on which it writes call options. As the writer of index call options, the Fund will forgo, during the option’s life, the opportunity to profit from increases in the value of the applicable index above the sum of the option premium received and the exercise price of the call option, but retains the risk of loss, minus the option premium received, should the value of the applicable index decline. When a call option is exercised, the Fund will be required to deliver an amount of cash determined by the excess of the value of the applicable index at contract termination over the exercise price of the option. Thus, the exercise of index call options sold by the Fund may require the Fund to sell portfolio securities to generate cash at inopportune times or for unattractive prices. The trading price of options may be adversely affected if the market for such options becomes less liquid or smaller. The Fund may close out a call option by buying the option instead of letting it expire or be exercised. There can be no assurance that a liquid market will exist when the Fund seeks to close out a call option position by buying the option.

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, particularly when there is no stated limit on the Fund’s use of derivatives. A derivative investment also involves the risks relating to the reference instrument underlying the investment.

Tax-Sensitive Investing Risk. The Fund may hold a security in order to achieve more favorable tax-treatment or to sell a security in order to create tax losses. The Fund’s utilization of various tax-management techniques may be curtailed or eliminated by tax legislation, regulation or interpretations. The Fund may not be able to minimize taxable distributions to shareholders and a portion of the Fund’s distributions may be taxable.

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 investment. 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. Depositary 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 economic 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.

Dividend Capture Trading Risk. The use of dividend capture strategies will expose the Fund to higher portfolio turnover, increased trading costs and potential for capital loss or gain, particularly in the event of significant short-term price movements of stocks subject to dividend capture trading.

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.

Leverage Risk. Certain Fund transactions may give rise to leverage. Leverage can result from a non-cash exposure to an underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. Leverage can also result from borrowings or issuance of preferred shares. The Fund may be required to segregate liquid assets or otherwise cover the Fund’s obligation created by a transaction that may give rise to leverage. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet segregation requirements. Leverage may cause the Fund’s NAV to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the Fund’s portfolio securities. The loss on leveraged investments may substantially exceed the initial investment.

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. For Funds that are both actively managed and use quantitative investment techniques, the portfolio manager also uses (or portfolio managers also use) quantitative investment techniques and analyses in making investment decisions for the Fund. For Funds that are both actively managed and use portfolio optimization, the portfolio manager also uses (or portfolio managers also use) quantitative portfolio optimization and risk management techniques in making investment decisions for the Fund. There can be no assurance that these techniques will achieve the desired results.

Recent Market Conditions. An outbreak of respiratory disease caused by a novel coronavirus was first detected in China in late 2019 and subsequently spread internationally. This coronavirus has 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 has resulted in a substantial economic downturn, which 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. The impact of this outbreak has negatively affected the worldwide economy, as well as the economies of individual countries and industries, and could continue to affect the market in significant and unforeseen ways. Other epidemics and pandemics that may arise in the future may have similar effects. 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.

General Fund Investing Risks. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objective. 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]

Trading and NAV Information

The Fund’s common shares have traded both at a premium and a discount to NAV. The Fund cannot predict whether its shares will trade in the future at a premium or discount to NAV. The provisions of the Investment Company Act of 1940, as amended (the “1940 Act”), generally require that the public offering price of common shares (less any underwriting commissions and discounts) must equal or exceed the NAV per share of a company’s common stock. The issuance of common shares may have an adverse effect on prices in the secondary market for the Fund’s common shares by increasing the number of common shares available, which may put downward pressure on the market price for the Fund’s common shares. Shares of common stock of closed-end investment companies frequently trade at a discount from NAV.

In addition, the Fund’s Board of Trustees has authorized the Fund to repurchase up to 10% of its common shares outstanding as of the last day of the prior calendar year at market prices when shares are trading at a discount to NAV. The share repurchase program does not obligate the Fund to purchase a specific amount of shares. The results of the share repurchase program are disclosed in the Fund’s annual and semi-annual reports to shareholders.

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 ($)		NAV per Share on Date of Market Price ($)		NAV Premium/(Discount) on Date of Market Price (%)
Fiscal Quarter Ended	High	Low	High	Low	High	Low
October 31, 2022	13.34	10.75	12.26	10.82	8.81	(0.65)
July 31, 2022	12.90	11.04	12.71	11.03	1.49	0.09
April 30, 2022	14.35	12.58	13.95	12.38	2.87	1.62
January 31, 2022	15.05	13.25	14.54	13.19	3.51	0.45
October 31, 2021	14.61	13.79	14.22	13.79	2.74	0.00
July 31, 2021	14.37	13.12	13.90	13.28	3.38	(1.20)
April 30, 2021	13.44	12.09	13.61	12.77	(1.25)	(5.32)
January 31, 2021	12.69	10.39	13.04	11.74	(2.68)	(11.50)

Capital Stock, Long-Term Debt, and Other Securities [Abstract]

Outstanding Security, Title [Text Block]

Common Shares

Outstanding Security, Not Held [Shares]

157,049,789