485BPOS

Registration No. (2-69719)
File No. (811-3105)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, DC 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933	☒
Pre­Effective Amendment No.	□
Post­Effective Amendment No. 72	☒

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940	☒
Amendment No. 65	☒

Oppenheimer Capital Appreciation Fund

(Exact Name of Registrant as Specified in Charter)

6803 South Tucson Way, Centennial, Colorado 80112-3924
(Address of Principal Executive Offices) (Zip Code)

(303) 768-3200

(Registrant’s Telephone Number, including Area Code)

Cynthia Lo Bessette, Esq.

OFI Global Asset Management, Inc.

225 Liberty Street, New York, New York 10281-1008
(Name and Address of Agent for Service)

It is proposed that this filing will become effective (check appropriate box):

☒ immediately upon filing pursuant to paragraph (b)

□ on  pursuant to paragraph (b)

□ 60 days after filing pursuant to paragraph (a)(1)

□ on pursuant to paragraph (a)(1)

□ 75 days after filing pursuant to paragraph (a)(2)

□ on pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

□ This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all the requirements for effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York and State of New York on the 9^th day of November 2017.

	Oppenheimer Capital Appreciation Fund
By:	Arthur P. Steinmetz*
	Arthur P. Steinmetz Trustee, President and Principal Executive Officer

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed below by the following persons in the capacities on the dates indicated:

Signatures	Title	Date
Brian F. Wruble*Brian F. Wruble	Chairman of the Board of Trustees	November 9, 2017
Arthur P. Steinmetz*Arthur P. Steinmetz	Trustee, President and Principal Executive Officer	November 9, 2017
Brian S. Petersen*Brian S. Petersen	Treasurer, Principal Financial & Accounting Officer	November 9, 2017
Beth Ann Brown*Beth Ann Brown	Trustee	November 9, 2017
Edmund P. Giambastiani, Jr.*Edmund P. Giambastiani, Jr.	Trustee	November 9, 2017
Elizabeth Krentzman*Elizabeth Krentzman	Trustee	November 9, 2017
Mary F. Miller*Mary F. Miller	Trustee	November 9, 2017
Joel W. Motley*Joel W. Motley	Trustee	November 9, 2017
Joanne Pace*Joanne Pace	Trustee	November 9, 2017
Daniel S. Vandivort*Daniel S. Vandivort	Trustee	November 9, 2017
*By: /s/ Taylor V. EdwardsTaylor V. Edwards, Attorney-in-Fact

EXHIBIT INDEX

Exhibit No.	Description
Ex-101.INS	XBRL Instance Document
Ex-101.SCH	XBRL Taxonomy Extension Schema Document
Ex-101.CAL	XBRL Taxonomy Extension Calculation Linkbase Document
Ex-101.DEF	XBRL Taxonomy Extension Definition Linkbase
Ex-101.LAB	XBRL Taxonomy Extension Labels Linkbase
Ex-101.PRE	XBRL Taxonomy Extension Presentation Linkbase Document

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Aug. 31, 2017
Registrant Name	dei_EntityRegistrantName	OPPENHEIMER CAPITAL APPRECIATION FUND
Central Index Key	dei_EntityCentralIndexKey	0000319767
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Oct. 26, 2017
Document Effective Date	dei_DocumentEffectiveDate	Oct. 27, 2017
Prospectus Date	rr_ProspectusDate	Oct. 27, 2017

XML

OPPENHEIMER CAPITAL APPRECIATION FUND

The Fund Summary

Investment Objective.

The Fund seeks capital appreciation.

Fees and Expenses of the Fund.

This table describes the fees and expenses that you may pay if you buy and hold or redeem shares of the Fund. You may qualify for sales charge discounts if you (or you and your spouse) invest, or agree to invest in the future, at least $25,000 in certain funds in the Oppenheimer family of funds. More information about these and other discounts and sales charge waivers is available from your financial professional and in the section “About Your Account” beginning on page 11 of the prospectus, in the appendix to the prospectus titled “Special Sales Charge Arrangements and Waivers” and in the section “How to Buy Shares” beginning on page 48 in the Fund’s Statement of Additional Information.

Shareholder Fees
(fees paid directly from your investment)

Shareholder Fees - OPPENHEIMER CAPITAL APPRECIATION FUND	Class A	Class B	Class C	Class R	Class Y	Class I
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	5.75%	none	none	none	none	none
Maximum Deferred Sales Charge (Load) (as % of the lower of original offering price or redemption proceeds)	none	5.00%	1.00%	none	none	none

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - OPPENHEIMER CAPITAL APPRECIATION FUND		Class A	Class B	Class C	Class R	Class Y	Class I
Management Fees	[1]	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%
Distribution and/or Service (12b-1) Fees	[1]	0.25%	1.00%	1.00%	0.50%	none	none
Other Expenses	[1]	0.23%	0.24%	0.23%	0.23%	0.23%	0.04%
Total Annual Fund Operating Expenses	[1]	1.07%	1.83%	1.82%	1.32%	0.82%	0.63%

Example.

The following 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 a class of shares of the Fund for the time periods indicated and then redeem all of your 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. Any applicable fee waivers and/or expense reimbursements would be reflected in the below examples for the first year only. Although your actual costs may be higher or lower, based on these assumptions your expenses would be as follows:

If shares are redeemed

Expense Example - OPPENHEIMER CAPITAL APPRECIATION FUND - USD ($)	1 Year	3 Years	5 Years	10 Years
Class A	678	897	1,134	1,812
Class B	688	881	1,199	1,780
Class C	287	578	994	2,156
Class R	135	421	728	1,601
Class Y	84	263	457	1,018
Class I	65	202	352	789

If shares are not redeemed

Expense Example, No Redemption - OPPENHEIMER CAPITAL APPRECIATION FUND - USD ($)	1 Year	3 Years	5 Years	10 Years
Class A	678	897	1,134	1,812
Class B	188	581	999	1,780
Class C	187	578	994	2,156
Class R	135	421	728	1,601
Class Y	84	263	457	1,018
Class I	65	202	352	789

Portfolio Turnover.

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 the annual fund operating expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 63% of the average value of its portfolio.

Principal Investment Strategies.

The Fund mainly invests in common stocks of “growth companies.” Growth companies are companies whose earnings and stock prices are expected to increase at a faster rate than the overall market. These may be newer companies or established companies of any capitalization range that the portfolio manager believes may appreciate in value over the long term. Currently, the Fund primarily focuses on established companies that are similar in size to companies in the S&P 500 Index or the Russell 1000 Growth Index. The Fund primarily invests in securities of U.S. issuers but may also invest in foreign securities. The portfolio manager looks for growth companies with stock prices that he believes are reasonable in relation to overall stock market valuations. In seeking broad diversification of the Fund’s portfolio among industries and market sectors, the portfolio manager focuses on a number of factors that may vary in particular cases and over time. Currently, the portfolio manager looks for:

• companies in business areas that have above-average growth potential

• companies with growth rates that the portfolio manager believes are sustainable over time

• stocks with reasonable valuations relative to their growth potential.

The Fund may sell the stocks of companies that the portfolio manager believes no longer meet the above criteria, but is not required to do so.

Principal Risks.

The price of the Fund’s shares can go up and down substantially. The value of the Fund’s investments may change because of broad changes in the markets in which the Fund invests or because of poor investment selection, which could cause the Fund to underperform other funds with similar investment objectives. There is no assurance that the Fund will achieve its investment objective. When you redeem your shares, they may be worth less than what you paid for them. These risks mean that you can lose money by investing in the Fund.

Risks of Investing in Stocks. The value of the Fund’s portfolio may be affected by changes in the stock markets. Stock markets may experience significant short-term volatility and may fall sharply at times. Adverse events in any part of the equity or fixed-income markets may have unexpected negative effects on other market segments. Different stock markets may behave differently from each other and U.S. stock markets may move in the opposite direction from one or more foreign stock markets.

The prices of individual stocks generally do not all move in the same direction at the same time. A variety of factors can affect the price of a particular company's stock. These factors may include, but are not limited to: poor earnings reports, a loss of customers, litigation against the company, general unfavorable performance of the company's sector or industry, or changes in government regulations affecting the company or its industry. To the extent that securities of a particular type are emphasized (for example foreign stocks, stocks of small- or mid-cap companies, growth or value stocks, or stocks of companies in a particular industry), fund share values may fluctuate more in response to events affecting the market for those types of securities.

Industry and Sector Focus. At times the Fund may increase the relative emphasis of its investments in a particular industry or sector. The prices of stocks of issuers in a particular industry or sector may go up and down in response to changes in economic conditions, government regulations, availability of basic resources or supplies, or other events that affect that industry or sector more than others. To the extent that the Fund increases the relative emphasis of its investments in a particular industry or sector, its share values may fluctuate in response to events affecting that industry or sector. To some extent that risk may be limited by the Fund’s policy of not concentrating its investments in any one industry.

Risks of Growth Investing. If a growth company’s earnings or stock price fails to increase as anticipated, or if its business plans do not produce the expected results, its securities may decline sharply. Growth companies may be newer or smaller companies that may experience greater stock price fluctuations and risks of loss than larger, more established companies. Newer growth companies tend to retain a large part of their earnings for research, development or investments in capital assets. Therefore, they may not pay any dividends for some time. Growth investing has gone in and out of favor during past market cycles and is likely to continue to do so. During periods when growth investing is out of favor or when markets are unstable, it may be more difficult to sell growth company securities at an acceptable price. Growth stocks may also be more volatile than other securities because of investor speculation.

Who Is the Fund Designed For? The Fund is designed primarily for investors seeking capital appreciation over the long term. Those investors should be willing to assume the risks of short-term share price fluctuations that are typical for a fund focusing on stocks. Because of its focus on long-term growth, the Fund may be more appropriate for investors with longer term investment goals. The Fund is not designed for investors needing current income. The Fund is not a complete investment program. You should carefully consider your own investment goals and risk tolerance before investing in the Fund.

An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

The Fund's Past Performance.

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance (for Class A Shares) from calendar year to calendar year and by showing how the Fund’s average annual returns for the periods of time shown in the table compare with those of a broad measure of market performance. The Fund’s past investment performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Sales charges and taxes are not reflected in the bar chart and if those charges were included, returns would be less than those shown. More recent performance information is available by calling the toll-free number on the back of this prospectus and on the Fund’s website: https://www.oppenheimerfunds.com/fund/CapitalAppreciationFund

Sales charges and taxes are not included and the returns would be lower if they were. During the period shown, the highest return for a calendar quarter was 18.94% (2nd Qtr 09) and the lowest return for a calendar quarter was -28.10% (4th Qtr 08). For the period from January 1, 2017 to September 30, 2017 the return before sales charges and taxes was 19.52%.

The following table shows the average annual total returns for each class of the Fund's shares. After-tax returns are calculated using the highest individual federal marginal income tax rates and do not reflect the impact of state or local taxes. Your actual after-tax returns, depending on your individual tax situation, may differ from those shown and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for only one class and after-tax returns for other classes will vary.

Average Annual Total Returns for the periods ended December 31, 2016

Average Annual Total Returns - OPPENHEIMER CAPITAL APPRECIATION FUND	1 Year	5 Years	10 Years	(or life of class, if less)		Inception Date
Class A Shares	(7.96%)	9.94%	4.31%			Jan. 22, 1981
Class A Shares | Return After Taxes on Distributions	(8.87%)	7.99%	3.34%			Jan. 22, 1981
Class A Shares | Return After Taxes on Distributions and Sale of Fund Shares	(3.77%)	7.74%	3.36%			Jan. 22, 1981
Class B Shares	(7.70%)	10.10%	4.42%			Nov. 01, 1995
Class C Shares	(4.00%)	10.40%	4.13%			Dec. 01, 1993
Class R Shares	(2.61%)	10.96%	4.65%			Mar. 01, 2001
Class Y Shares	(2.12%)	11.57%	5.29%			Nov. 03, 1997
Class I Shares	(1.93%)	11.74%		11.66%		Dec. 29, 2011
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	11.96%	14.66%	6.95%	14.54%	[1]
Russell 1000 Growth Index (reflects no deduction for fees, expenses, or taxes)	7.08%	14.50%	8.33%	14.40%	[1]

[1] Expenses have been restated to reflect current fees.

[1] From 12/29/11

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	OPPENHEIMER CAPITAL APPRECIATION FUND
Prospectus Date	rr_ProspectusDate	Oct. 27, 2017
OPPENHEIMER CAPITAL APPRECIATION FUND
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	The Fund Summary
Objective [Heading]	rr_ObjectiveHeading	Investment Objective.
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks capital appreciation.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund.
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold or redeem shares of the Fund. You may qualify for sales charge discounts if you (or you and your spouse) invest, or agree to invest in the future, at least $25,000 in certain funds in the Oppenheimer family of funds. More information about these and other discounts and sales charge waivers is available from your financial professional and in the section “About Your Account” beginning on page 11 of the prospectus, in the appendix to the prospectus titled “Special Sales Charge Arrangements and Waivers” and in the section “How to Buy Shares” beginning on page 48 in the Fund’s Statement of Additional Information.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover.
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 the annual fund operating expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 63% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	63.00%
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge discounts if you (or you and your spouse) invest, or agree to invest in the future, at least $25,000 in certain funds in the Oppenheimer family of funds.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 25,000
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	Expenses have been restated to reflect current fees.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example.
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following 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 a class of shares of the Fund for the time periods indicated and then redeem all of your 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. Any applicable fee waivers and/or expense reimbursements would be reflected in the below examples for the first year only. Although your actual costs may be higher or lower, based on these assumptions your expenses would be as follows:
Expense Example by, Year, Caption [Text]	rr_ExpenseExampleByYearCaption	If shares are redeemed
Expense Example, No Redemption, By Year, Caption [Text]	rr_ExpenseExampleNoRedemptionByYearCaption	If shares are not redeemed
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies.
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund mainly invests in common stocks of “growth companies.” Growth companies are companies whose earnings and stock prices are expected to increase at a faster rate than the overall market. These may be newer companies or established companies of any capitalization range that the portfolio manager believes may appreciate in value over the long term. Currently, the Fund primarily focuses on established companies that are similar in size to companies in the S&P 500 Index or the Russell 1000 Growth Index. The Fund primarily invests in securities of U.S. issuers but may also invest in foreign securities. The portfolio manager looks for growth companies with stock prices that he believes are reasonable in relation to overall stock market valuations. In seeking broad diversification of the Fund’s portfolio among industries and market sectors, the portfolio manager focuses on a number of factors that may vary in particular cases and over time. Currently, the portfolio manager looks for: companies in business areas that have above-average growth potential companies with growth rates that the portfolio manager believes are sustainable over time stocks with reasonable valuations relative to their growth potential. The Fund may sell the stocks of companies that the portfolio manager believes no longer meet the above criteria, but is not required to do so.
Risk [Heading]	rr_RiskHeading	Principal Risks.
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The price of the Fund’s shares can go up and down substantially. The value of the Fund’s investments may change because of broad changes in the markets in which the Fund invests or because of poor investment selection, which could cause the Fund to underperform other funds with similar investment objectives. There is no assurance that the Fund will achieve its investment objective. When you redeem your shares, they may be worth less than what you paid for them. These risks mean that you can lose money by investing in the Fund. Risks of Investing in Stocks. The value of the Fund’s portfolio may be affected by changes in the stock markets. Stock markets may experience significant short-term volatility and may fall sharply at times. Adverse events in any part of the equity or fixed-income markets may have unexpected negative effects on other market segments. Different stock markets may behave differently from each other and U.S. stock markets may move in the opposite direction from one or more foreign stock markets. The prices of individual stocks generally do not all move in the same direction at the same time. A variety of factors can affect the price of a particular company's stock. These factors may include, but are not limited to: poor earnings reports, a loss of customers, litigation against the company, general unfavorable performance of the company's sector or industry, or changes in government regulations affecting the company or its industry. To the extent that securities of a particular type are emphasized (for example foreign stocks, stocks of small- or mid-cap companies, growth or value stocks, or stocks of companies in a particular industry), fund share values may fluctuate more in response to events affecting the market for those types of securities. Industry and Sector Focus. At times the Fund may increase the relative emphasis of its investments in a particular industry or sector. The prices of stocks of issuers in a particular industry or sector may go up and down in response to changes in economic conditions, government regulations, availability of basic resources or supplies, or other events that affect that industry or sector more than others. To the extent that the Fund increases the relative emphasis of its investments in a particular industry or sector, its share values may fluctuate in response to events affecting that industry or sector. To some extent that risk may be limited by the Fund’s policy of not concentrating its investments in any one industry. Risks of Growth Investing. If a growth company’s earnings or stock price fails to increase as anticipated, or if its business plans do not produce the expected results, its securities may decline sharply. Growth companies may be newer or smaller companies that may experience greater stock price fluctuations and risks of loss than larger, more established companies. Newer growth companies tend to retain a large part of their earnings for research, development or investments in capital assets. Therefore, they may not pay any dividends for some time. Growth investing has gone in and out of favor during past market cycles and is likely to continue to do so. During periods when growth investing is out of favor or when markets are unstable, it may be more difficult to sell growth company securities at an acceptable price. Growth stocks may also be more volatile than other securities because of investor speculation. Who Is the Fund Designed For? The Fund is designed primarily for investors seeking capital appreciation over the long term. Those investors should be willing to assume the risks of short-term share price fluctuations that are typical for a fund focusing on stocks. Because of its focus on long-term growth, the Fund may be more appropriate for investors with longer term investment goals. The Fund is not designed for investors needing current income. The Fund is not a complete investment program. You should carefully consider your own investment goals and risk tolerance before investing in the Fund. An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Lose Money [Text]	rr_RiskLoseMoney	These risks mean that you can lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	The Fund's Past Performance.
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance (for Class A Shares) from calendar year to calendar year and by showing how the Fund’s average annual returns for the periods of time shown in the table compare with those of a broad measure of market performance. The Fund’s past investment performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Sales charges and taxes are not reflected in the bar chart and if those charges were included, returns would be less than those shown. More recent performance information is available by calling the toll-free number on the back of this prospectus and on the Fund’s website: https://www.oppenheimerfunds.com/fund/CapitalAppreciationFund
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance (for Class A Shares) from calendar year to calendar year and by showing how the Fund’s average annual returns for the periods of time shown in the table compare with those of a broad measure of market performance.
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.oppenheimerfunds.com/fund/CapitalAppreciationFund
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past investment performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	Sales charges and taxes are not reflected in the bar chart and if those charges were included, returns would be less than those shown.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Sales charges and taxes are not included and the returns would be lower if they were. During the period shown, the highest return for a calendar quarter was 18.94% (2nd Qtr 09) and the lowest return for a calendar quarter was -28.10% (4th Qtr 08). For the period from January 1, 2017 to September 30, 2017 the return before sales charges and taxes was 19.52%.
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for the periods ended December 31, 2016
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using the highest individual federal marginal income tax rates and do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns, depending on your individual tax situation, may differ from those shown and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown for only one class and after-tax returns for other classes will vary.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The following table shows the average annual total returns for each class of the Fund's shares. After-tax returns are calculated using the highest individual federal marginal income tax rates and do not reflect the impact of state or local taxes. Your actual after-tax returns, depending on your individual tax situation, may differ from those shown and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for only one class and after-tax returns for other classes will vary.
OPPENHEIMER CAPITAL APPRECIATION FUND | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.75%
Maximum Deferred Sales Charge (Load) (as % of the lower of original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOther	none
Management Fees	rr_ManagementFeesOverAssets	0.59%	[1]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%	[1]
Other Expenses	rr_OtherExpensesOverAssets	0.23%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.07%	[1]
1 Year	rr_ExpenseExampleYear01	$ 678
3 Years	rr_ExpenseExampleYear03	897
5 Years	rr_ExpenseExampleYear05	1,134
10 Years	rr_ExpenseExampleYear10	1,812
1 Year	rr_ExpenseExampleNoRedemptionYear01	678
3 Years	rr_ExpenseExampleNoRedemptionYear03	897
5 Years	rr_ExpenseExampleNoRedemptionYear05	1,134
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,812
2007	rr_AnnualReturn2007	13.76%
2008	rr_AnnualReturn2008	(45.90%)
2009	rr_AnnualReturn2009	43.58%
2010	rr_AnnualReturn2010	9.14%
2011	rr_AnnualReturn2011	(1.57%)
2012	rr_AnnualReturn2012	13.69%
2013	rr_AnnualReturn2013	29.24%
2014	rr_AnnualReturn2014	15.07%
2015	rr_AnnualReturn2015	3.22%
2016	rr_AnnualReturn2016	(2.34%)
Year to Date Return, Label	rr_YearToDateReturnLabel	For the period from January 1, 2017 to September 30, 2017
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2017
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	19.52%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	18.94%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(28.10%)
1 Year	rr_AverageAnnualReturnYear01	(7.96%)
5 Years	rr_AverageAnnualReturnYear05	9.94%
10 Years	rr_AverageAnnualReturnYear10	4.31%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 22, 1981
OPPENHEIMER CAPITAL APPRECIATION FUND | Class B
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as % of the lower of original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOther	5.00%
Management Fees	rr_ManagementFeesOverAssets	0.59%	[1]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%	[1]
Other Expenses	rr_OtherExpensesOverAssets	0.24%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.83%	[1]
1 Year	rr_ExpenseExampleYear01	$ 688
3 Years	rr_ExpenseExampleYear03	881
5 Years	rr_ExpenseExampleYear05	1,199
10 Years	rr_ExpenseExampleYear10	1,780
1 Year	rr_ExpenseExampleNoRedemptionYear01	188
3 Years	rr_ExpenseExampleNoRedemptionYear03	581
5 Years	rr_ExpenseExampleNoRedemptionYear05	999
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,780
1 Year	rr_AverageAnnualReturnYear01	(7.70%)
5 Years	rr_AverageAnnualReturnYear05	10.10%
10 Years	rr_AverageAnnualReturnYear10	4.42%
Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 01, 1995
OPPENHEIMER CAPITAL APPRECIATION FUND | Class C
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as % of the lower of original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOther	1.00%
Management Fees	rr_ManagementFeesOverAssets	0.59%	[1]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%	[1]
Other Expenses	rr_OtherExpensesOverAssets	0.23%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.82%	[1]
1 Year	rr_ExpenseExampleYear01	$ 287
3 Years	rr_ExpenseExampleYear03	578
5 Years	rr_ExpenseExampleYear05	994
10 Years	rr_ExpenseExampleYear10	2,156
1 Year	rr_ExpenseExampleNoRedemptionYear01	187
3 Years	rr_ExpenseExampleNoRedemptionYear03	578
5 Years	rr_ExpenseExampleNoRedemptionYear05	994
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,156
1 Year	rr_AverageAnnualReturnYear01	(4.00%)
5 Years	rr_AverageAnnualReturnYear05	10.40%
10 Years	rr_AverageAnnualReturnYear10	4.13%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 01, 1993
OPPENHEIMER CAPITAL APPRECIATION FUND | Class R
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as % of the lower of original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOther	none
Management Fees	rr_ManagementFeesOverAssets	0.59%	[1]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.50%	[1]
Other Expenses	rr_OtherExpensesOverAssets	0.23%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.32%	[1]
1 Year	rr_ExpenseExampleYear01	$ 135
3 Years	rr_ExpenseExampleYear03	421
5 Years	rr_ExpenseExampleYear05	728
10 Years	rr_ExpenseExampleYear10	1,601
1 Year	rr_ExpenseExampleNoRedemptionYear01	135
3 Years	rr_ExpenseExampleNoRedemptionYear03	421
5 Years	rr_ExpenseExampleNoRedemptionYear05	728
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,601
1 Year	rr_AverageAnnualReturnYear01	(2.61%)
5 Years	rr_AverageAnnualReturnYear05	10.96%
10 Years	rr_AverageAnnualReturnYear10	4.65%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 01, 2001
OPPENHEIMER CAPITAL APPRECIATION FUND | Class Y
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as % of the lower of original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOther	none
Management Fees	rr_ManagementFeesOverAssets	0.59%	[1]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none	[1]
Other Expenses	rr_OtherExpensesOverAssets	0.23%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.82%	[1]
1 Year	rr_ExpenseExampleYear01	$ 84
3 Years	rr_ExpenseExampleYear03	263
5 Years	rr_ExpenseExampleYear05	457
10 Years	rr_ExpenseExampleYear10	1,018
1 Year	rr_ExpenseExampleNoRedemptionYear01	84
3 Years	rr_ExpenseExampleNoRedemptionYear03	263
5 Years	rr_ExpenseExampleNoRedemptionYear05	457
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,018
1 Year	rr_AverageAnnualReturnYear01	(2.12%)
5 Years	rr_AverageAnnualReturnYear05	11.57%
10 Years	rr_AverageAnnualReturnYear10	5.29%
Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 03, 1997
OPPENHEIMER CAPITAL APPRECIATION FUND | Class I
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as % of the lower of original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOther	none
Management Fees	rr_ManagementFeesOverAssets	0.59%	[1]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none	[1]
Other Expenses	rr_OtherExpensesOverAssets	0.04%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.63%	[1]
1 Year	rr_ExpenseExampleYear01	$ 65
3 Years	rr_ExpenseExampleYear03	202
5 Years	rr_ExpenseExampleYear05	352
10 Years	rr_ExpenseExampleYear10	789
1 Year	rr_ExpenseExampleNoRedemptionYear01	65
3 Years	rr_ExpenseExampleNoRedemptionYear03	202
5 Years	rr_ExpenseExampleNoRedemptionYear05	352
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 789
1 Year	rr_AverageAnnualReturnYear01	(1.93%)
5 Years	rr_AverageAnnualReturnYear05	11.74%
(or life of class, if less)	rr_AverageAnnualReturnSinceInception	11.66%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 29, 2011
OPPENHEIMER CAPITAL APPRECIATION FUND | Return After Taxes on Distributions | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(8.87%)
5 Years	rr_AverageAnnualReturnYear05	7.99%
10 Years	rr_AverageAnnualReturnYear10	3.34%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 22, 1981
OPPENHEIMER CAPITAL APPRECIATION FUND | Return After Taxes on Distributions and Sale of Fund Shares | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(3.77%)
5 Years	rr_AverageAnnualReturnYear05	7.74%
10 Years	rr_AverageAnnualReturnYear10	3.36%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 22, 1981
OPPENHEIMER CAPITAL APPRECIATION FUND | S&P 500 Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	11.96%
5 Years	rr_AverageAnnualReturnYear05	14.66%
10 Years	rr_AverageAnnualReturnYear10	6.95%
(or life of class, if less)	rr_AverageAnnualReturnSinceInception	14.54%	[2]
OPPENHEIMER CAPITAL APPRECIATION FUND | Russell 1000 Growth Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	7.08%
5 Years	rr_AverageAnnualReturnYear05	14.50%
10 Years	rr_AverageAnnualReturnYear10	8.33%
(or life of class, if less)	rr_AverageAnnualReturnSinceInception	14.40%	[2]

[1] Expenses have been restated to reflect current fees.

[2] From 12/29/11

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	OPPENHEIMER CAPITAL APPRECIATION FUND
Prospectus Date	rr_ProspectusDate	Oct. 27, 2017
Document Creation Date	dei_DocumentCreationDate	Oct. 26, 2017