0001097077 blcsfi1:S000001973Member blcsfi1:ServiceSharesMember 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:ServiceSharesMember blcsfi1:C000052209Member 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:ServiceSharesMember rr:AfterTaxesOnDistributionsMember blcsfi1:C000052209Member 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:ServiceSharesMember rr:AfterTaxesOnDistributionsAndSalesMember blcsfi1:C000052209Member 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:ServiceSharesMember blcsfi1:RussellOneThousandIndexMember 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:InvestorInstitutionalAndRSharesMember 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:InvestorInstitutionalAndRSharesMember blcsfi1:C000005171Member 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:InvestorInstitutionalAndRSharesMember blcsfi1:C000005172Member 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:InvestorInstitutionalAndRSharesMember blcsfi1:C000005173Member 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:InvestorInstitutionalAndRSharesMember blcsfi1:C000005174Member 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:InvestorInstitutionalAndRSharesMember blcsfi1:C000005175Member 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:InvestorInstitutionalAndRSharesMember rr:AfterTaxesOnDistributionsMember blcsfi1:C000005171Member 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:InvestorInstitutionalAndRSharesMember rr:AfterTaxesOnDistributionsAndSalesMember blcsfi1:C000005171Member 2012-01-29 2013-01-28 0001097077 blcsfi1:S000001973Member blcsfi1:InvestorInstitutionalAndRSharesMember blcsfi1:RussellOneThousandIndexMember 2012-01-29 2013-01-28 0001097077 2012-01-29 2013-01-28 pure iso4217:USD Fund Overview Key Facts About BlackRock Large Cap Core Fund Investment Objective The investment objective of BlackRock Large Cap Core Fund (“Core Fund” or the “Fund”), a series of BlackRock Large Cap Series Funds, Inc., is to seek long-term capital growth. In other words, the Fund tries to choose investments that will increase in value. Fees and Expenses of the Fund This table describes the fees and expenses that you may pay if you buy and hold Service Shares of Core Fund. Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 0.0047 0.0025 0.0033 0.0025 0.0008 0.0105 Example: This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all 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. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 107 334 579 1283 Portfolio Turnover: The Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Portfolio’s performance. During the most recent fiscal year, the Portfolio’s portfolio turnover rate was 128% of the average value of its portfolio. 1.28 Principal Investment Strategies of the Fund Core Fund seeks to achieve its objective by investing at least 80% of its assets in equity securities, primarily common stock, of large cap companies located in the United States that BlackRock Advisors, LLC (“BlackRock”) selects from among those that are, at the time of purchase, included in the Fund’s benchmark, the Russell 1000® Index. Equity securities consist primarily of common stock, preferred stock, securities convertible into common stock and securities or other instruments whose price is linked to the value of common stock. Large cap companies are companies that at the time of purchase have a market capitalization equal to or greater than the top 80% of the companies that comprise the Russell 1000® Index. As of June 22, 2012, the most recent rebalance date, the lowest market capitalization in this group was $1.4 billion. The market capitalizations of companies in the index change with market conditions and the composition of the index. The Fund will use an investment approach that blends growth and value. Growth companies are those whose earnings growth potential appears to the Fund management team to be greater than the market in general and whose revenue growth is expected to continue for an extended period. Stocks of growth companies typically pay relatively low dividends and sell at relatively high valuations. Value companies are those that appear to be undervalued by the market as measured by certain financial formulas. The Fund is a “feeder” fund that invests all of its assets in Master Core Portfolio, which has the same investment objective and strategies as the Fund. All investments are made at the Portfolio level. This structure is sometimes called a “master/feeder” structure. The Fund’s investment results will correspond directly to the investment results of the Portfolio. For simplicity, the prospectus uses the terms “Core Fund” or “Fund” (as applicable) to include the Portfolio. Principal Risks of Investing in the Fund Risk is inherent in all investing. The value of your investment in Core Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. The following is a summary description of principal risks of investing in the Fund.<ul type="square"><li>Equity Securities Risk — Stock markets are volatile. The price of equity securities fluctuates based on changes in a company’s financial condition and overall market and economic conditions.</li></ul><ul type="square"><li>Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion and value investments have performed better during periods of economic recovery. Therefore, these investment styles may over time go in and out of favor. At times when the investment style used by the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</li></ul><ul type="square"><li>Market Risk and Selection Risk — Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by Fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.</li></ul> Performance Information You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. The Service Shares commenced operations on September 24, 2007. Prior to inception of the Service Share class, the performance shown is based on Core Fund’s Institutional Shares, which are offered by a separate prospectus. The returns for the Service Shares, however, are adjusted to reflect the service fees applicable to the Service Shares. The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. The table compares the Service Share performance to that of the Russell 1000® Index. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. Updated information on the Fund’s results can be obtained by visiting http://www.blackrock.com/funds or can be obtained by phone at (800) 882-0052. The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. (800) 882-0052 http://www.blackrock.com/funds As with all such investments, past performance (before and after taxes) is not an indication of future results. Service Shares ANNUAL TOTAL RETURNS Core Fund As of 12/31 Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. During the ten-year period shown in the bar chart, the highest return for a quarter was 14.81% (quarter ended June 30, 2003) and the lowest return for a quarter was –21.25% (quarter ended September 30, 2011). highest return 2003-06-30 0.1481 lowest return 2011-09-30 -0.2125 0.3158 0.1541 0.1306 0.128 0.0488 -0.374 0.2047 0.1104 -0.0028 0.143 As of 12/31/12 Average Annual Total Returns 0.143 0.1426 0.093 0.1642 -0.0092 -0.0104 -0.0086 0.0192 0.0684 0.0593 0.0638 0.0752 Fund Overview Key Facts About BlackRock Large Cap Core Fund Investment Objective Fees and Expenses of the Fund After-tax returns are calculated using the historical highest individual Federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. However, the table includes all applicable fees and sales charges. After-tax returns are calculated using the historical highest individual Federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. <div style="display:none">~ http://www.blackrock.com/role/ScheduleAnnualFundOperatingExpensesBlackRockLargeCapCoreFundServiceShares column period compact * ~</div> <div style="display:none">~ http://www.blackrock.com/role/ScheduleExpenseExampleTransposedBlackRockLargeCapCoreFundServiceShares column period compact * ~</div> <div style="display:none">~ http://www.blackrock.com/role/ScheduleAnnualTotalReturnsBlackRockLargeCapCoreFundServiceSharesBarChart column period compact * ~</div> <div style="display:none">~ http://www.blackrock.com/role/ScheduleAverageAnnualTotalReturnsTransposedBlackRockLargeCapCoreFundServiceShares column period compact * ~</div> Shareholder Fees (fees paid directly from your investment) Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Example: Portfolio Turnover: Principal Investment Strategies of the Fund Principal Risks of Investing in the Fund Performance Information Investor A Shares ANNUAL TOTAL RETURNS Core Fund As of 12/31 As of 12/31/12 Average Annual Total Returns The investment objective of BlackRock Large Cap Core Fund (“Core Fund” or the “Fund”), a series of BlackRock Large Cap Series Funds, Inc. (the “Corporation”), is to seek long-term capital growth. In other words, the Fund tries to choose investments that will increase in value. This table describes the fees and expenses that you may pay if you buy and hold shares of Core Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in the fund complex advised by BlackRock Advisors, LLC (“BlackRock”). More information about these and other discounts is available from your financial professional and in the “Details About the Share Classes” section on page 29 of the Fund’s prospectus and in the “Purchase of Shares” section on page II-58 of the Fund’s statement of additional information. 25000 You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in the fund complex advised by BlackRock Advisors, LLC (“BlackRock”). This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all 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. Although your actual costs may be higher or lower, based on these assumptions your costs would be: You would pay the following expenses if you did not redeem your shares: The Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Portfolio’s performance. During the most recent fiscal year, the Portfolio’s portfolio turnover rate was 128% of the average value of its portfolio. 1.28 Core Fund seeks to achieve its objective by investing at least 80% of its assets in equity securities, primarily common stock, of large cap companies located in the United States that BlackRock selects from among those that are, at the time of purchase, included in the Fund’s benchmark, the Russell 1000® Index. Equity securities consist primarily of common stock, preferred stock, securities convertible into common stock and securities or other instruments whose price is linked to the value of common stock. Large cap companies are companies that at the time of purchase have a market capitalization equal to or greater than the top 80% of the companies that comprise the Russell 1000® Index. As of June 22, 2012, the most recent rebalance date, the lowest market capitalization in this group was $1.4 billion. The market capitalizations of companies in the index change with market conditions and the composition of the index. The Fund will use an investment approach that blends growth and value. Growth companies are those whose earnings growth potential appears to the Fund management team to be greater than the market in general and whose revenue growth is expected to continue for an extended period. Stocks of growth companies typically pay relatively low dividends and sell at relatively high valuations. Value companies are those that appear to be undervalued by the market as measured by certain financial formulas. The Fund is a “feeder” fund that invests all of its assets in Master Core Portfolio, which has the same investment objective and strategies as the Fund. All investments are made at the Portfolio level. This structure is sometimes called a “master/feeder” structure. The Fund’s investment results will correspond directly to the investment results of the Portfolio. For simplicity, the prospectus uses the terms “Core Fund” or “Fund” (as applicable) to include the Portfolio. http://www.blackrock.com/funds The information shows you how Core Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. (800) 882-0052 As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. The information shows you how Core Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. The table compares the Fund’s performance to that of the Russell 1000® Index. The returns for Class R Shares prior to January 3, 2003, the commencement of operations of Class R Shares, are based upon the performance of the Fund’s Institutional Shares. The returns for Class R Shares, however, are adjusted to reflect the distribution and service (12b-1) fees applicable to Class R Shares. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If BlackRock and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund’s returns would have been lower. Updated information on the Fund’s results can be obtained by visiting http://www.blackrock.com/funds or can be obtained by phone at (800) 882-0052. During the ten-year period shown in the bar chart, the highest return for a quarter was 14.87% (quarter ended June 30, 2003) and the lowest return for a quarter was –21.23% (quarter ended September 30, 2011). highest return lowest return 0.1487 -0.2123 2011-09-30 2003-06-30 After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Investor B, Investor C, Institutional and Class R Shares will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Investor B, Investor C, Institutional and Class R Shares will vary. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. 0.3164 0.1537 0.1305 0.1279 0.0486 -0.3747 0.2046 0.1102 -0.0003 0.1423 Risk is inherent in all investing. The value of your investment in Core Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. The following is a summary description of principal risks of investing in the Fund.<ul type="square"><li>Equity Securities Risk — Stock markets are volatile. The price of equity securities fluctuates based on changes in a company’s financial condition and overall market and economic conditions.</li></ul><ul type="square"><li>Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion and value investments have performed better during periods of economic recovery. Therefore, these investment styles may over time go in and out of favor. At times when the investment style used by the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</li></ul><ul type="square"><li>Market Risk and Selection Risk — Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by Fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.</li></ul> You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. 0.0525 0 0 0 0 0.045 0.01 0 0 0 0.0047 0.0047 0.0047 0.0047 0.0047 0.0025 0.01 0.01 0 0.005 0.0056 0.0071 0.0058 0.0043 0.0056 0.0025 0.0025 0.0025 0.0025 0.0025 0.0128 0.0218 0.0153 0.009 0.0205 -0.0021 -0.0014 0.0114 0.0197 0.0205 0.009 0.0153 635 650 308 92 156 896 1012 643 287 483 1178 1350 1103 498 834 1977 2268 2379 1108 1824 200 208 662 643 1150 1103 2268 2379 0.0823 0.0759 0.0535 0.0884 0.1222 0.1474 0.1382 0.1642 -0.0198 -0.0223 -0.0182 -0.0211 -0.0181 -0.007 -0.0135 0.0192 0.0627 0.0574 0.0537 0.0617 0.0594 0.071 0.0653 0.0752 <div style="display:none">~ http://www.blackrock.com/role/ScheduleShareholderFeesBlackRockLargeCapCoreFund column period compact * ~</div> <div style="display:none">~ http://www.blackrock.com/role/ScheduleAnnualFundOperatingExpensesBlackRockLargeCapCoreFund column period compact * ~</div> <div style="display:none">~ http://www.blackrock.com/role/ScheduleExpenseExampleTransposedBlackRockLargeCapCoreFund column period compact * ~</div> <div style="display:none">~ http://www.blackrock.com/role/ScheduleExpenseExampleNoRedemptionTransposedBlackRockLargeCapCoreFund column period compact * ~</div> <div style="display:none">~ http://www.blackrock.com/role/ScheduleAnnualTotalReturnsBlackRockLargeCapCoreFundBarChart column period compact * ~</div> <div style="display:none">~ http://www.blackrock.com/role/ScheduleAverageAnnualTotalReturnsTransposedBlackRockLargeCapCoreFund column period compact * ~</div> 0.0018 0.0033 0.0031 0.0046 0.0031 A contingent deferred sales charge (“CDSC”) of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at time of purchase as part of an investment of $1,000,000 or more. Miscellaneous Other Expenses have been restated to reflect current fees. BLACKROCK LARGE CAP SERIES FUNDS, INC. 0001097077 Other false 2013-02-01 2013-02-01 2012-09-30 2013-01-28 The fees and expenses shown in the table and the example that follows include both the expenses of Core Fund and Core Fund’s share of the allocated expenses of Master Large Cap Core Portfolio (“Master Core Portfolio” or the “Portfolio”). Management Fees are paid by Master Core Portfolio. February 1, 2014 The Total Annual Fund Operating Expenses do not correlate to the ratio of expenses to average net assets given in the Fund’s most recent annual report which does not include the restatement of Miscellaneous Other Expenses to reflect current fees. The fees and expenses shown in the table and the example that follows include both the expenses of Core Fund and Core Fund’s share of the allocated expenses of Master Large Cap Core Portfolio (“Master Core Portfolio” or the “Portfolio”), a series of Master Large Cap Series LLC. Management Fees are paid by Master Core Portfolio. A contingent deferred sales charge ("CDSC") of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at time of purchase as part of an investment of $1,000,000 or more. There is no CDSC on Investor C Shares after one year. The fees and expenses shown in the table and the example that follows include both the expenses of Core Fund and Core Fund's share of the allocated expenses of Master Large Cap Core Portfolio ("Master Core Portfolio" or the "Portfolio"), a series of Master Large Cap Series LLC. Management Fees are paid by Master Core Portfolio. A portion of the Fund's total return was attributable to proceeds received in the fiscal period ended September 30, 2009 in a settlement of litigation. The fees and expenses shown in the table and the example that follows include both the expenses of Core Fund and Core Fund's share of the allocated expenses of Master Large Cap Core Portfolio ("Master Core Portfolio" or the "Portfolio"). Management Fees are paid by Master Core Portfolio. The Total Annual Fund Operating Expenses do not correlate to the ratio of expenses to average net assets given in the Fund's most recent annual report which does not include the restatement of Miscellaneous Other Expenses to reflect current fees. As described in the "Management of the Funds" section of the Fund's prospectus on pages 44-49, BlackRock has contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 1.14% (for Investor A Shares) and 1.97% (for Investor B Shares) of average daily net assets until February 1, 2014. The agreement may be terminated upon 90 days' notice by a majority of the non-interested directors of the Corporation or by a vote of a majority of the outstanding voting securities of Core Fund. Miscellaneous Other Expenses have been restated to reflect current fees. The CDSC is 4.50% if shares are redeemed in less than one year. The CDSC for Investor B Shares decreases for redemptions made in subsequent years. After six years there is no CDSC on Investor B Shares. (See the section "Details About the Share Classes - Investor B Shares" in the Fund's prospectus for the complete schedule of CDSCs.)