485BPOS

Registration Nos. 333-04753/811-07639

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933/X/

Post-Effective Amendment No. 43/X/

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940 /X/

Amendment No. 43/X/

T. ROWE PRICE INSTITUTIONAL EQUITY FUNDS, INC.

Exact Name of Registrant as Specified in Charter

100 East Pratt Street, Baltimore, Maryland 21202
Address of Principal Executive Offices

410-345-2000
Registrant’s Telephone Number, Including Area Code

David Oestreicher

100 East Pratt Street, Baltimore, Maryland 21202
Name and Address of Agent for Service

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

/X/Immediately upon filing pursuant to paragraph (b)

//On (date) pursuant to paragraph (b)

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

//On (date) pursuant to paragraph (a)(1)

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

//On (date) 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.

Page 2

EXHIBITS

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

Page 3

Signatures

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant certifies that it meets all of 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, duly authorized, in the City of Baltimore, State of Maryland, this May 15, 2018.

T. ROWE PRICE INSTITUTIONAL EQUITY FUNDS, INC.

/s/Edward C. Bernard

By:Edward C. Bernard

Chairman of the Board

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

Signature	Title	Date
/s/Edward C. Bernard	Chairman of the Board	May 15, 2018
Edward C. Bernard	(Chief Executive Officer)
/s/Catherine D. Mathews	Treasurer	May 15, 2018
Catherine D. Mathews	(Chief Financial Officer)
	and Vice President
*
Teresa Bryce Bazemore	Director	May 15, 2018
*
Ronald J. Daniels	Director	May 15, 2018
*
Bruce W. Duncan	Director	May 15, 2018
*
Robert J. Gerrard, Jr.	Director	May 15, 2018
*
Paul F. McBride	Director	May 15, 2018
*
Cecilia E. Rouse	Director	May 15, 2018
*
John G. Schreiber	Director	May 15, 2018

Page 4

/s/Robert W. Sharps	Director and President	May 15, 2018
Robert W. Sharps
*
Mark. R. Tercek	Director	May 15, 2018
*/s/David Oestreicher	Vice President and	May 15, 2018
David Oestreicher	Attorney-In-Fact

Page 5

T. ROWE PRICE BALANCED FUND, INC.

T. ROWE PRICE BLUE CHIP GROWTH FUND, INC.

T. ROWE PRICE CALIFORNIA TAX-FREE INCOME TRUST

T. ROWE PRICE CAPITAL APPRECIATION FUND

T. ROWE PRICE CAPITAL APPRECIATION FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION & INCOME FUND, INC.

T. ROWE PRICE CAPITAL OPPORTUNITY FUND, INC.

T. ROWE PRICE CORPORATE INCOME FUND, INC.

T. ROWE PRICE CREDIT OPPORTUNITIES FUND, INC.

T. ROWE PRICE DIVERSIFIED MID-CAP GROWTH FUND, INC.

T. ROWE PRICE DIVIDEND GROWTH FUND, INC.

T. ROWE PRICE EQUITY INCOME FUND

T. ROWE PRICE EQUITY INCOME FUND, INC.

T. ROWE PRICE EQUITY SERIES, INC.

T. ROWE PRICE FINANCIAL SERVICES FUND, INC.

T. ROWE PRICE FIXED INCOME SERIES, INC.

T. ROWE PRICE FLOATING RATE FUND, INC.

T. ROWE PRICE GLOBAL ALLOCATION FUND, INC.

T. ROWE PRICE GLOBAL MULTI-SECTOR BOND FUND, INC.

T. ROWE PRICE GLOBAL REAL ESTATE FUND, INC.

T. ROWE PRICE GLOBAL TECHNOLOGY FUND, INC.

T. ROWE PRICE GNMA FUND

T. ROWE PRICE GNMA FUND, INC.

T. ROWE PRICE GOVERNMENT MONEY FUND, INC.

T. ROWE PRICE GROWTH & INCOME FUND, INC.

T. ROWE PRICE GROWTH STOCK FUND, INC.

T. ROWE PRICE HEALTH SCIENCES FUND, INC.

T. ROWE PRICE HIGH YIELD FUND, INC.

T. ROWE PRICE INDEX TRUST, INC.

T. ROWE PRICE INFLATION PROTECTED BOND FUND, INC.

T. ROWE PRICE INSTITUTIONAL EQUITY FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INCOME FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERMEDIATE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL INDEX FUND, INC.

T. ROWE PRICE INTERNATIONAL SERIES, INC.

T. ROWE PRICE LIMITED DURATION INFLATION FOCUSED BOND FUND, INC.

T. ROWE PRICE MEDIA & TELECOMMUNICATIONS FUND, INC.

T. ROWE PRICE MID-CAP GROWTH FUND, INC.

T. ROWE PRICE MID-CAP VALUE FUND, INC.

T. ROWE PRICE MULTI-SECTOR ACCOUNT PORTFOLIOS, INC.

T. ROWE PRICE MULTI-STRATEGY TOTAL RETURN FUND, INC.

T. ROWE PRICE NEW AMERICA GROWTH FUND

T. ROWE PRICE NEW AMERICA GROWTH FUND, INC.
T. ROWE PRICE NEW ERA FUND, INC.

T. ROWE PRICE NEW HORIZONS FUND, INC.

T. ROWE PRICE NEW INCOME FUND, INC.

T. ROWE PRICE PERSONAL STRATEGY FUNDS, INC.

T. ROWE PRICE QUANTITATIVE MANAGEMENT FUNDS, INC.

Page 6

T. ROWE PRICE REAL ASSETS FUND, INC.

T. ROWE PRICE REAL ESTATE FUND, INC.

T. ROWE PRICE RESERVE INVESTMENT FUNDS, INC.

T. ROWE PRICE RETIREMENT FUNDS, INC.

T. ROWE PRICE SCIENCE & TECHNOLOGY FUND, INC.

T. ROWE PRICE SHORT-TERM BOND FUND, INC.

T. ROWE PRICE SMALL-CAP STOCK FUND, INC.

T. ROWE PRICE SMALL-CAP VALUE FUND, INC.

T. ROWE PRICE SPECTRUM FUND, INC.

T. ROWE PRICE STATE TAX-FREE INCOME TRUST

T. ROWE PRICE STATE TAX-FREE FUNDS, INC.

T. ROWE PRICE SUMMIT FUNDS, INC.

T. ROWE PRICE SUMMIT MUNICIPAL FUNDS, INC.

T. ROWE PRICE TAX-EFFICIENT FUNDS, INC.

T. ROWE PRICE TAX-EXEMPT MONEY FUND, INC.

T. ROWE PRICE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE TAX-FREE INCOME FUND, INC.

T. ROWE PRICE TAX-FREE SHORT-INTERMEDIATE FUND, INC.

T. ROWE PRICE TOTAL RETURN FUND, INC.

T. ROWE PRICE U.S. BOND ENHANCED INDEX FUND, INC.

T. ROWE PRICE U.S. LARGE-CAP CORE FUND, INC.

T. ROWE PRICE U.S. TREASURY FUNDS, INC.

T. ROWE PRICE VALUE FUND, INC.

POWER OF ATTORNEY

RESOLVED, that the Corporation does hereby constitute and authorize Edward C. Bernard, Margery K. Neale, and David Oestreicher, and each of them individually, their true and lawful attorneys and agents to take any and all action and execute any and all instruments which said attorneys and agents may deem necessary or advisable to enable the Corporation/Trust to comply with the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, and any rules, regulations, orders or other requirements of the United States Securities and Exchange Commission thereunder, in connection with the registration under the Securities Act of 1933, as amended, of shares of the Corporation/Trust, to be offered by the Corporation/Trust, and the registration of the Corporation/Trust under the Investment Company Act of 1940, as amended, including specifically, but without limitation of the foregoing, power and authority to sign the name of the Corporation/Trust on its behalf, and to sign the names of each of such directors/trustees and officers on his or her behalf as such director/trustee or officer to any (i) Registration Statement on Form N-1A or N-14 of the Corporation/Trust filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended; (ii) Registration Statement on Form N-1A or N-14 of the Corporation/Trust under the Investment Company Act of 1940, as amended; (iii) amendment or supplement (including, but not limited to, Post-Effective Amendments adding additional series or classes of the Corporation/Trust) to said Registration Statement; and (iv) instruments or documents filed or to be filed as a part of or in connection with such Registration Statement, including Articles Supplementary, Articles of Amendment, and other instruments with respect to the Articles of Incorporation or Master Trust Agreement of the Corporation/Trust.

IN WITNESS WHEREOF, the above named Corporations/Trusts have caused these presents to be signed and the same attested by its Secretary, each thereunto duly authorized by its Board of Directors/Trustees, and each of the undersigned has hereunto set his or her hand and seal as of the day set opposite his or her name.

Page 7

ALL CORPORATIONS/TRUSTS /s/Edward C. Bernard
Edward C. Bernard /s/Catherine D. Mathews	Chairman of the Board (Principal Executive Officer) Director/Trustee	April 27, 2017
Catherine D. Mathews /s/Anthony W. Deering	Treasurer (Principal Financial Officer) Vice President	April 27, 2017
Anthony W. Deering /s/Bruce W. Duncan	Director/Trustee	April 27, 2017
Bruce W. Duncan /s/Robert J. Gerrard, Jr.	Director/Trustee	April 27, 2017
Robert J. Gerrard, Jr. /s/Paul F. McBride	Director/Trustee	April 27, 2017
Paul F. McBride /s/Cecilia E. Rouse	Director/Trustee	April 27, 2017
Cecilia E. Rouse /s/John G. Schreiber	Director/Trustee	April 27, 2017
John G. Schreiber /s/Mark R. Tercek	Director/Trustee	April 27, 2017
Mark R. Tercek	Director/Trustee	April 27, 2017

(Signatures Continued)

Page 8

ROBERT W. SHARPS, Director/Trustee

T. ROWE PRICE BALANCED FUND, INC.

T. ROWE PRICE BLUE CHIP GROWTH FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION FUND

T. ROWE PRICE CAPITAL APPRECIATION FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION & INCOME FUND, INC.

T. ROWE PRICE CAPITAL OPPORTUNITY FUND, INC.

T. ROWE PRICE DIVERSIFIED MID-CAP GROWTH FUND, INC.

T. ROWE PRICE DIVIDEND GROWTH FUND, INC.

T. ROWE PRICE EQUITY INCOME FUND

T. ROWE PRICE EQUITY INCOME FUND, INC.

T. ROWE PRICE EQUITY SERIES, INC.

T. ROWE PRICE FINANCIAL SERVICES FUND, INC.

T. ROWE PRICE GLOBAL ALLOCATION FUND, INC.

T. ROWE PRICE GLOBAL REAL ESTATE FUND, INC.

T. ROWE PRICE GLOBAL TECHNOLOGY FUND, INC.

T. ROWE PRICE GROWTH & INCOME FUND, INC.

T. ROWE PRICE GROWTH STOCK FUND, INC.

T. ROWE PRICE HEALTH SCIENCES FUND, INC.

T. ROWE INDEX TRUST, INC.

T. ROWE PRICE INSTITUTIONAL EQUITY FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL INDEX FUND, INC.

T. ROWE PRICE INTERNATIONAL SERIES, INC.

T. ROWE PRICE MEDIA & TELECOMMUNICATIONS FUND, INC.

T. ROWE PRICE MID-CAP GROWTH FUND, INC.

T. ROWE PRICE MID-CAP VALUE FUND, INC.

T. ROWE PRICE MULTI-STRATEGY TOTAL RETURN FUND, INC.

T. ROWE PRICE NEW AMERICA GROWTH FUND

T. ROWE PRICE NEW AMERICA GROWTH FUND, INC.

T. ROWE PRICE NEW ERA FUND, INC.

T. ROWE PRICE NEW HORIZONS FUND, INC.

T. ROWE PRICE PERSONAL STRATEGY FUNDS, INC.

T. ROWE PRICE QUANTITATIVE MANAGEMENT FUNDS, INC.

T. ROWE PRICE REAL ASSETS FUND, INC.

T. ROWE PRICE REAL ESTATE FUND, INC.

T. ROWE PRICE RETIREMENT FUNDS, INC.

T. ROWE PRICE SCIENCE & TECHNOLOGY FUND, INC.

T. ROWE PRICE SMALL-CAP STOCK FUND, INC.

T. ROWE PRICE SMALL-CAP VALUE FUND, INC.

T. ROWE PRICE SPECTRUM FUND, INC.

T. ROWE PRICE TAX-EFFICIENT FUNDS, INC.

T. ROWE PRICE U.S. LARGE-CAP CORE FUND, INC.

T. ROWE PRICE VALUE FUND, INC.

/s/Robert W. Sharps

Robert W. Sharps April 27, 2017

(Signatures Continued)

Page 9

EDWARD A. WIESE, Director/Trustee

T. ROWE PRICE CALIFORNIA TAX-FREE INCOME TRUST

T. ROWE PRICE CORPORATE INCOME FUND, INC.

T. ROWE PRICE CREDIT OPPORTUNITIES FUND, INC.

T. ROWE PRICE FIXED INCOME SERIES, INC.

T. ROWE PRICE FLOATING RATE FUND, INC.

T. ROWE PRICE GLOBAL MULTI-SECTOR BOND FUND, INC.

T. ROWE PRICE GNMA FUND

T. ROWE PRICE GNMA FUND, INC.

T. ROWE PRICE GOVERNMENT MONEY FUND, INC.

T. ROWE PRICE HIGH YIELD FUND, INC.

T. ROWE PRICE INSTITUTIONAL INCOME FUNDS, INC.

T. ROWE PRICE INFLATION PROTECTED BOND FUND, INC.

T. ROWE PRICE INTERMEDIATE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE LIMITED DURATION INFLATION FOCUSED BOND FUND, INC.

T. ROWE PRICE MULTI-SECTOR ACCOUNT PORTFOLIOS, INC.

T. ROWE PRICE NEW INCOME FUND, INC.

T. ROWE PRICE RESERVE INVESTMENT FUNDS, INC.

T. ROWE PRICE SHORT-TERM BOND FUND, INC.

T. ROWE PRICE STATE TAX-FREE INCOME TRUST

T. ROWE PRICE STATE TAX-FREE FUNDS, INC.

T. ROWE PRICE SUMMIT FUNDS, INC.

T. ROWE PRICE SUMMIT MUNICIPAL FUNDS, INC.

T. ROWE PRICE TAX-EXEMPT MONEY FUND, INC.

T. ROWE PRICE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE TAX-FREE INCOME FUND, INC.

T. ROWE PRICE TAX-FREE SHORT-INTERMEDIATE FUND, INC.

T. ROWE PRICE U.S. BOND ENHANCED INDEX FUND, INC.

T. ROWE PRICE U.S. TREASURY FUNDS, INC.

/s/Edward A. Wiese

Edward A. Wiese April 27, 2017

(Signatures Continued)

Page 10

ATTEST:

/s/Darrell N. Braman

Darrell N. Braman, Secretary

Page 11

T. ROWE PRICE BALANCED FUND, INC.

T. ROWE PRICE BLUE CHIP GROWTH FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION & INCOME FUND, INC.

T. ROWE PRICE CAPITAL OPPORTUNITY FUND, INC.

T. ROWE PRICE CORPORATE INCOME FUND, INC.

T. ROWE PRICE CREDIT OPPORTUNITIES FUND, INC.

T. ROWE PRICE DIVERSIFIED MID-CAP GROWTH FUND, INC.

T. ROWE PRICE DIVIDEND GROWTH FUND, INC.

T. ROWE PRICE EQUITY INCOME FUND, INC.

T. ROWE PRICE EQUITY SERIES, INC.

T. ROWE PRICE FINANCIAL SERVICES FUND, INC.

T. ROWE PRICE FIXED INCOME SERIES, INC.

T. ROWE PRICE FLOATING RATE FUND, INC.

T. ROWE PRICE GLOBAL ALLOCATION FUND, INC.

T. ROWE PRICE GLOBAL MULTI-SECTOR BOND FUND, INC.

T. ROWE PRICE GLOBAL REAL ESTATE FUND, INC.

T. ROWE PRICE GLOBAL TECHNOLOGY FUND, INC.

T. ROWE PRICE GNMA FUND, INC.

T. ROWE PRICE GOVERNMENT MONEY FUND, INC.

T. ROWE PRICE GROWTH & INCOME FUND, INC.

T. ROWE PRICE GROWTH STOCK FUND, INC.

T. ROWE PRICE HEALTH SCIENCES FUND, INC.

T. ROWE PRICE HIGH YIELD FUND, INC.

T. ROWE PRICE INDEX TRUST, INC.

T. ROWE PRICE INFLATION PROTECTED BOND FUND, INC.

T. ROWE PRICE INSTITUTIONAL EQUITY FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INCOME FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERMEDIATE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL INDEX FUND, INC.

T. ROWE PRICE INTERNATIONAL SERIES, INC.

T. ROWE PRICE LIMITED DURATION INFLATION FOCUSED BOND FUND, INC.

T. ROWE PRICE MEDIA & TELECOMMUNICATIONS FUND, INC.

T. ROWE PRICE MID-CAP GROWTH FUND, INC.

T. ROWE PRICE MID-CAP VALUE FUND, INC.

T. ROWE PRICE MULTI-SECTOR ACCOUNT PORTFOLIOS, INC.

T. ROWE PRICE MULTI-STRATEGY TOTAL RETURN FUND, INC.

T. ROWE PRICE NEW AMERICA GROWTH FUND, INC.
T. ROWE PRICE NEW ERA FUND, INC.

T. ROWE PRICE NEW HORIZONS FUND, INC.

T. ROWE PRICE NEW INCOME FUND, INC.

T. ROWE PRICE PERSONAL STRATEGY FUNDS, INC.

T. ROWE PRICE QUANTITATIVE MANAGEMENT FUNDS, INC.

T. ROWE PRICE REAL ASSETS FUND, INC.

T. ROWE PRICE REAL ESTATE FUND, INC.

T. ROWE PRICE RESERVE INVESTMENT FUNDS, INC.

T. ROWE PRICE RETIREMENT FUNDS, INC.

T. ROWE PRICE SCIENCE & TECHNOLOGY FUND, INC.

Page 12

T. ROWE PRICE SHORT-TERM BOND FUND, INC.

T. ROWE PRICE SMALL-CAP STOCK FUND, INC.

T. ROWE PRICE SMALL-CAP VALUE FUND, INC.

T. ROWE PRICE SPECTRUM FUND, INC.

T. ROWE PRICE STATE TAX-FREE FUNDS, INC.

T. ROWE PRICE SUMMIT FUNDS, INC.

T. ROWE PRICE SUMMIT MUNICIPAL FUNDS, INC.

T. ROWE PRICE TAX-EFFICIENT FUNDS, INC.

T. ROWE PRICE TAX-EXEMPT MONEY FUND, INC.

T. ROWE PRICE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE TAX-FREE INCOME FUND, INC.

T. ROWE PRICE TAX-FREE SHORT-INTERMEDIATE FUND, INC.

T. ROWE PRICE TOTAL RETURN FUND, INC.

T. ROWE PRICE U.S. BOND ENHANCED INDEX FUND, INC.

T. ROWE PRICE U.S. LARGE-CAP CORE FUND, INC.

T. ROWE PRICE U.S. TREASURY FUNDS, INC.

T. ROWE PRICE VALUE FUND, INC.

POWER OF ATTORNEY

RESOLVED, that the Corporation does hereby constitute and authorize Edward C. Bernard, Margery K. Neale, and David Oestreicher, and each of them individually, their true and lawful attorneys and agents to take any and all action and execute any and all instruments which said attorneys and agents may deem necessary or advisable to enable the Corporation to comply with the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, and any rules, regulations, orders or other requirements of the United States Securities and Exchange Commission thereunder, in connection with the registration under the Securities Act of 1933, as amended, of shares of the Corporation, to be offered by the Corporation, and the registration of the Corporation under the Investment Company Act of 1940, as amended, including specifically, but without limitation of the foregoing, power and authority to sign the name of the Corporation on its behalf, and to sign the names of each of such directors and officers on his or her behalf as such director or officer to any (i) Registration Statement on Form N-1A or N-14 of the Corporation filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended; (ii) Registration Statement on Form N-1A or N-14 of the Corporation under the Investment Company Act of 1940, as amended; (iii) amendment or supplement (including, but not limited to, Post-Effective Amendments adding additional series or classes of the Corporation) to said Registration Statement; and (iv) instruments or documents filed or to be filed as a part of or in connection with such Registration Statement, including Articles Supplementary, Articles of Amendment, and other instruments with respect to the Articles of Incorporation of the Corporation.

IN WITNESS WHEREOF, the above named Corporations have caused these presents to be signed and the same attested by its Secretary, each thereunto duly authorized by its Board of Directors, and the undersigned has hereunto set his or her hand and seal as of the day set opposite his or her name.

/s/Teresa Bryce Bazemore
Teresa Bryce Bazemore, Director	Date: January 1, 2018

ATTEST:

/s/Darrell N. Braman

Darrell N. Braman, Secretary

Page 13

T. ROWE PRICE BALANCED FUND, INC.

T. ROWE PRICE BLUE CHIP GROWTH FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION FUND, INC.

T. ROWE PRICE CAPITAL APPRECIATION & INCOME FUND, INC.

T. ROWE PRICE CAPITAL OPPORTUNITY FUND, INC.

T. ROWE PRICE CORPORATE INCOME FUND, INC.

T. ROWE PRICE CREDIT OPPORTUNITIES FUND, INC.

T. ROWE PRICE DIVERSIFIED MID-CAP GROWTH FUND, INC.

T. ROWE PRICE DIVIDEND GROWTH FUND, INC.

T. ROWE PRICE EQUITY INCOME FUND, INC.

T. ROWE PRICE EQUITY SERIES, INC.

T. ROWE PRICE FINANCIAL SERVICES FUND, INC.

T. ROWE PRICE FIXED INCOME SERIES, INC.

T. ROWE PRICE FLOATING RATE FUND, INC.

T. ROWE PRICE GLOBAL ALLOCATION FUND, INC.

T. ROWE PRICE GLOBAL MULTI-SECTOR BOND FUND, INC.

T. ROWE PRICE GLOBAL REAL ESTATE FUND, INC.

T. ROWE PRICE GLOBAL TECHNOLOGY FUND, INC.

T. ROWE PRICE GNMA FUND, INC.

T. ROWE PRICE GOVERNMENT MONEY FUND, INC.

T. ROWE PRICE GROWTH & INCOME FUND, INC.

T. ROWE PRICE GROWTH STOCK FUND, INC.

T. ROWE PRICE HEALTH SCIENCES FUND, INC.

T. ROWE PRICE HIGH YIELD FUND, INC.

T. ROWE PRICE INDEX TRUST, INC.

T. ROWE PRICE INFLATION PROTECTED BOND FUND, INC.

T. ROWE PRICE INSTITUTIONAL EQUITY FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INCOME FUNDS, INC.

T. ROWE PRICE INSTITUTIONAL INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERMEDIATE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE INTERNATIONAL FUNDS, INC.

T. ROWE PRICE INTERNATIONAL INDEX FUND, INC.

T. ROWE PRICE INTERNATIONAL SERIES, INC.

T. ROWE PRICE LIMITED DURATION INFLATION FOCUSED BOND FUND, INC.

T. ROWE PRICE MEDIA & TELECOMMUNICATIONS FUND, INC.

T. ROWE PRICE MID-CAP GROWTH FUND, INC.

T. ROWE PRICE MID-CAP VALUE FUND, INC.

T. ROWE PRICE MULTI-SECTOR ACCOUNT PORTFOLIOS, INC.

T. ROWE PRICE MULTI-STRATEGY TOTAL RETURN FUND, INC.

T. ROWE PRICE NEW AMERICA GROWTH FUND, INC.
T. ROWE PRICE NEW ERA FUND, INC.

T. ROWE PRICE NEW HORIZONS FUND, INC.

T. ROWE PRICE NEW INCOME FUND, INC.

T. ROWE PRICE PERSONAL STRATEGY FUNDS, INC.

T. ROWE PRICE QUANTITATIVE MANAGEMENT FUNDS, INC.

T. ROWE PRICE REAL ASSETS FUND, INC.

T. ROWE PRICE REAL ESTATE FUND, INC.

T. ROWE PRICE RESERVE INVESTMENT FUNDS, INC.

T. ROWE PRICE RETIREMENT FUNDS, INC.

T. ROWE PRICE SCIENCE & TECHNOLOGY FUND, INC.

Page 14

T. ROWE PRICE SHORT-TERM BOND FUND, INC.

T. ROWE PRICE SMALL-CAP STOCK FUND, INC.

T. ROWE PRICE SMALL-CAP VALUE FUND, INC.

T. ROWE PRICE SPECTRUM FUND, INC.

T. ROWE PRICE STATE TAX-FREE FUNDS, INC.

T. ROWE PRICE SUMMIT FUNDS, INC.

T. ROWE PRICE SUMMIT MUNICIPAL FUNDS, INC.

T. ROWE PRICE TAX-EFFICIENT FUNDS, INC.

T. ROWE PRICE TAX-EXEMPT MONEY FUND, INC.

T. ROWE PRICE TAX-FREE HIGH YIELD FUND, INC.

T. ROWE PRICE TAX-FREE INCOME FUND, INC.

T. ROWE PRICE TAX-FREE SHORT-INTERMEDIATE FUND, INC.

T. ROWE PRICE TOTAL RETURN FUND, INC.

T. ROWE PRICE U.S. BOND ENHANCED INDEX FUND, INC.

T. ROWE PRICE U.S. LARGE-CAP CORE FUND, INC.

T. ROWE PRICE U.S. TREASURY FUNDS, INC.

T. ROWE PRICE VALUE FUND, INC.

POWER OF ATTORNEY

RESOLVED, that the Corporation does hereby constitute and authorize Edward C. Bernard, Margery K. Neale, and David Oestreicher, and each of them individually, their true and lawful attorneys and agents to take any and all action and execute any and all instruments which said attorneys and agents may deem necessary or advisable to enable the Corporation to comply with the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, and any rules, regulations, orders or other requirements of the United States Securities and Exchange Commission thereunder, in connection with the registration under the Securities Act of 1933, as amended, of shares of the Corporation, to be offered by the Corporation, and the registration of the Corporation under the Investment Company Act of 1940, as amended, including specifically, but without limitation of the foregoing, power and authority to sign the name of the Corporation on its behalf, and to sign the names of each of such directors and officers on his or her behalf as such director or officer to any (i) Registration Statement on Form N-1A or N-14 of the Corporation filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended; (ii) Registration Statement on Form N-1A or N-14 of the Corporation under the Investment Company Act of 1940, as amended; (iii) amendment or supplement (including, but not limited to, Post-Effective Amendments adding additional series or classes of the Corporation) to said Registration Statement; and (iv) instruments or documents filed or to be filed as a part of or in connection with such Registration Statement, including Articles Supplementary, Articles of Amendment, and other instruments with respect to the Articles of Incorporation of the Corporation.

IN WITNESS WHEREOF, the above named Corporations have caused these presents to be signed and the same attested by its Secretary, each thereunto duly authorized by its Board of Directors, and the undersigned has hereunto set his or her hand and seal as of the day set opposite his or her name.

/s/Ronald J. Daniels
Ronald J. Daniels, Director	Date: January 1, 2018

ATTEST:

/s/Darrell N. Braman

Darrell N. Braman, Secretary

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Dec. 31, 2017
Registrant Name	dei_EntityRegistrantName	T. Rowe Price Institutional Equity Funds, Inc.
Central Index Key	dei_EntityCentralIndexKey	0001012968
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Apr. 26, 2018
Document Effective Date	dei_DocumentEffectiveDate	May 01, 2018
Prospectus Date	rr_ProspectusDate	May 01, 2018

XML

T. Rowe Price Institutional Large-Cap Core Growth Fund

T. Rowe Price

Institutional Large-Cap Core Growth Fund

SUMMARY

Investment Objective

The fund seeks to provide long-term capital growth through investments in the common stocks of large-cap growth companies.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Annual Fund Operating Expenses	T. Rowe Price Institutional Large-Cap Core Growth Fund T. Rowe Price Institutional Large-Cap Core Growth Fund
Management fees	0.55%
Other expenses	0.02%
Total annual fund operating expenses	0.57%

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, 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:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Large-Cap Core Growth Fund | T. Rowe Price Institutional Large-Cap Core Growth Fund | USD ($)	58	183	318	714

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 41.1% of the average value of its portfolio.

Investments, Risks, and Performance

Principal Investment Strategies

The fund follows a growth-oriented approach to stock selection and expects to normally invest in stocks of approximately 100 to 130 companies. The fund will normally invest at least 80% of its net assets (including any borrowings for investment purposes) in large-cap companies. The fund defines a large-cap company as one whose market capitalization is larger than the median market capitalization of companies in the Russell 1000 Growth Index, a widely used benchmark of the largest U.S. growth stocks. As of December 31, 2017, the (unweighted) median market capitalization of companies in the Russell 1000 Growth Index was approximately $11.8 billion. The market capitalizations of the companies in the fund’s portfolio and the Russell index change over time; the fund will not automatically sell or cease to purchase stock of a company it already owns just because the company’s market capitalization falls below the median market capitalization of companies in the Russell index. The fund may at times invest significantly in certain sectors, such as the information technology sector.

From a broad universe of about 1,000 large-cap stocks, the fund targets companies that, in the investment adviser’s view, are well established in their industries and have the potential for above-average earnings growth. The fund focuses on companies with leading market positions, seasoned management, and strong financial fundamentals. The fund may at times invest significantly in stocks of technology companies. The fund’s investment approach reflects its belief that solid company fundamentals (with emphasis on strong growth in earnings per share or operating cash flow) combined with a positive industry outlook should ultimately reward investors with strong investment performance. Generally, the adviser seeks out companies with strong free cash flow growth, good balance sheets, high returns on capital, and above-average earnings growth and profit margins. The adviser makes an effort to avoid overpaying for a company’s growth prospects by examining a company’s stock valuation relative to its own history, its industry peers, and the overall equity market.

Once stocks are selected for inclusion in the fund’s portfolio, the adviser monitors each company and may build positions carefully over time and scale back positions when the adviser believes valuations have become less compelling. The adviser will eliminate holdings for various reasons, including a loss of faith in management, a change in the adviser’s assessment of a company’s fundamentals, an overextension in share price valuations, or to replace stocks with potentially better investment opportunities.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

While most assets will typically be invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’s objective.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of U.S. stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks Investing primarily in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment. Securities issued by large-cap companies tend to be less volatile than securities issued by smaller companies. However, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and may be unable to respond as quickly to competitive challenges.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the information technology sector. Companies in the information technology sector can be adversely affected by, among other things, intense competition, earnings disappointments, and rapid obsolescence of products and services due to technological innovations or changing consumer preferences.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes or restrictions on gaining access to sales proceeds for foreign investors.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Institutional Large-Cap Core Growth Fund
Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	3/31/12	18.63%	Worst Quarter	12/31/08	-24.93%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Average Annual Total Returns

Periods ended
December 31, 2017

Average Annual Total Returns - T. Rowe Price Institutional Large-Cap Core Growth Fund	1 Year	5 Years	10 Years	Inception date
T. Rowe Price Institutional Large-Cap Core Growth Fund	36.50%	18.90%	10.56%	Sep. 30, 2003
T. Rowe Price Institutional Large-Cap Core Growth Fund | Returns after taxes on distributions	36.05%	18.69%	10.43%	Sep. 30, 2003
T. Rowe Price Institutional Large-Cap Core Growth Fund | Returns after taxes on distributions and sale of fund shares	21.03%	15.38%	8.73%	Sep. 30, 2003
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	21.83%	15.79%	8.50%
Lipper Large-Cap Growth Funds Index	31.85%	15.90%	8.20%

Updated performance information is available through troweprice.com.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional Equity Funds, Inc.

Prospectus Date

rr_ProspectusDate

May 01, 2018

T. Rowe Price Institutional Large-Cap Core Growth Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. Rowe Price

Institutional Large-Cap Core Growth Fund

SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks to provide long-term capital growth through investments in the common stocks of large-cap growth companies.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Fees and Expenses of the Fund

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 41.1% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

41.10%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund follows a growth-oriented approach to stock selection and expects to normally invest in stocks of approximately 100 to 130 companies. The fund will normally invest at least 80% of its net assets (including any borrowings for investment purposes) in large-cap companies. The fund defines a large-cap company as one whose market capitalization is larger than the median market capitalization of companies in the Russell 1000 Growth Index, a widely used benchmark of the largest U.S. growth stocks. As of December 31, 2017, the (unweighted) median market capitalization of companies in the Russell 1000 Growth Index was approximately $11.8 billion. The market capitalizations of the companies in the fund’s portfolio and the Russell index change over time; the fund will not automatically sell or cease to purchase stock of a company it already owns just because the company’s market capitalization falls below the median market capitalization of companies in the Russell index. The fund may at times invest significantly in certain sectors, such as the information technology sector.

From a broad universe of about 1,000 large-cap stocks, the fund targets companies that, in the investment adviser’s view, are well established in their industries and have the potential for above-average earnings growth. The fund focuses on companies with leading market positions, seasoned management, and strong financial fundamentals. The fund may at times invest significantly in stocks of technology companies. The fund’s investment approach reflects its belief that solid company fundamentals (with emphasis on strong growth in earnings per share or operating cash flow) combined with a positive industry outlook should ultimately reward investors with strong investment performance. Generally, the adviser seeks out companies with strong free cash flow growth, good balance sheets, high returns on capital, and above-average earnings growth and profit margins. The adviser makes an effort to avoid overpaying for a company’s growth prospects by examining a company’s stock valuation relative to its own history, its industry peers, and the overall equity market.

Once stocks are selected for inclusion in the fund’s portfolio, the adviser monitors each company and may build positions carefully over time and scale back positions when the adviser believes valuations have become less compelling. The adviser will eliminate holdings for various reasons, including a loss of faith in management, a change in the adviser’s assessment of a company’s fundamentals, an overextension in share price valuations, or to replace stocks with potentially better investment opportunities.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

While most assets will typically be invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’s objective.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of U.S. stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks Investing primarily in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment. Securities issued by large-cap companies tend to be less volatile than securities issued by smaller companies. However, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and may be unable to respond as quickly to competitive challenges.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the information technology sector. Companies in the information technology sector can be adversely affected by, among other things, intense competition, earnings disappointments, and rapid obsolescence of products and services due to technological innovations or changing consumer preferences.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes or restrictions on gaining access to sales proceeds for foreign investors.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

troweprice.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

Institutional Large-Cap Core Growth Fund
Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	3/31/12	18.63%	Worst Quarter	12/31/08	-24.93%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns

Periods ended
December 31, 2017

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Large-Cap Core Growth Fund | T. Rowe Price Institutional Large-Cap Core Growth Fund

Risk/Return:

rr_RiskReturnAbstract

Management fees

rr_ManagementFeesOverAssets

0.55%

Other expenses

rr_OtherExpensesOverAssets

0.02%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.57%

1 year

rr_ExpenseExampleYear01

$ 58

3 years

rr_ExpenseExampleYear03

183

5 years

rr_ExpenseExampleYear05

318

10 years

rr_ExpenseExampleYear10

$ 714

2008

rr_AnnualReturn2008

(42.61%)

2009

rr_AnnualReturn2009

42.99%

2010

rr_AnnualReturn2010

16.37%

2011

rr_AnnualReturn2011

1.47%

2012

rr_AnnualReturn2012

18.48%

2013

rr_AnnualReturn2013

41.44%

2014

rr_AnnualReturn2014

9.30%

2015

rr_AnnualReturn2015

11.34%

2016

rr_AnnualReturn2016

1.12%

2017

rr_AnnualReturn2017

36.50%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

18.63%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(24.93%)

1 Year

rr_AverageAnnualReturnYear01

36.50%

5 Years

rr_AverageAnnualReturnYear05

18.90%

10 Years

rr_AverageAnnualReturnYear10

10.56%

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2003

T. Rowe Price Institutional Large-Cap Core Growth Fund | Returns after taxes on distributions | T. Rowe Price Institutional Large-Cap Core Growth Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

36.05%

5 Years

rr_AverageAnnualReturnYear05

18.69%

10 Years

rr_AverageAnnualReturnYear10

10.43%

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2003

T. Rowe Price Institutional Large-Cap Core Growth Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional Large-Cap Core Growth Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

21.03%

5 Years

rr_AverageAnnualReturnYear05

15.38%

10 Years

rr_AverageAnnualReturnYear10

8.73%

Inception date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2003

T. Rowe Price Institutional Large-Cap Core Growth Fund | S&P 500 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

21.83%

5 Years

rr_AverageAnnualReturnYear05

15.79%

10 Years

rr_AverageAnnualReturnYear10

8.50%

T. Rowe Price Institutional Large-Cap Core Growth Fund | Lipper Large-Cap Growth Funds Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

31.85%

5 Years

rr_AverageAnnualReturnYear05

15.90%

10 Years

rr_AverageAnnualReturnYear10

8.20%

XML

T. Rowe Price Institutional Large-Cap Growth Fund

T. Rowe Price

Institutional Large-Cap Growth Fund

SUMMARY

Investment Objective

The fund seeks to provide long-term capital appreciation through investments in common stocks of growth companies.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Annual Fund Operating Expenses	T. Rowe Price Institutional Large-Cap Growth Fund T. Rowe Price Institutional Large-Cap Growth Fund
Management fees	0.55%
Other expenses	0.01%
Total annual fund operating expenses	0.56%

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, 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:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Large-Cap Growth Fund | T. Rowe Price Institutional Large-Cap Growth Fund | USD ($)	57	179	313	701

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 36.1% of the average value of its portfolio.

Investments, Risks, and Performance

Principal Investment Strategies

In taking a growth approach to stock selection, the fund will normally invest at least 80% of its net assets (including any borrowings for investment purposes) in the common stocks of large-cap companies. The fund defines a large-cap company as one whose market capitalization is larger than the median market capitalization of companies in the Russell 1000 Growth Index, a widely used benchmark of the largest U.S. growth stocks. As of December 31, 2017, the median market capitalization of companies in the Russell 1000 Growth Index was approximately $11.8 billion. The market capitalizations of the companies in the fund’s portfolio and the Russell index change over time; the fund will not automatically sell or cease to purchase stock of a company it already owns just because the company’s market capitalization falls below the median market capitalization of companies in the Russell index. The fund may at times invest significantly in certain sectors, such as the information technology sector.

We generally look for companies with an above-average rate of earnings and cash flow growth and a lucrative niche in the economy that gives them the ability to sustain earnings momentum even during times of slow economic growth. As growth investors, we believe that when a company increases its earnings faster than both inflation and the overall economy, the market will eventually reward it with a higher stock price.

The fund is “nondiversified,” meaning it may invest a greater portion of its assets in a single issuer and own more of the issuer’s voting securities than is permissible for a “diversified” fund.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

While most assets will typically be invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’s objective.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

Emerging markets risks The risks of foreign investing are heightened for securities of issuers in emerging market countries. Emerging market countries tend to have economic structures that are less diverse and mature, and political systems that are less stable, than those of developed countries. In addition to all of the risks of investing in foreign developed markets, emerging markets are more susceptible to governmental interference, local taxes being imposed on foreign investments, restrictions on gaining access to sales proceeds, and less liquid and less efficient trading markets.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks Investing primarily in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment. Securities issued by large-cap companies tend to be less volatile than securities issued by smaller companies. However, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and may be unable to respond as quickly to competitive challenges.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the information technology sector. Companies in the information technology sector can be adversely affected by, among other things, intense competition, earnings disappointments, and rapid obsolescence of products and services due to technological innovations or changing consumer preferences.

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Institutional Large-Cap Growth Fund
Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	19.94%	Worst Quarter	12/31/08	-22.72%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Average Annual Total Returns

Periods ended
December 31, 2017

Average Annual Total Returns - T. Rowe Price Institutional Large-Cap Growth Fund	1 Year	5 Years	10 Years	Inception date
T. Rowe Price Institutional Large-Cap Growth Fund	37.82%	19.63%	11.60%	Oct. 31, 2001
T. Rowe Price Institutional Large-Cap Growth Fund | Returns after taxes on distributions	35.00%	18.34%	10.98%	Oct. 31, 2001
T. Rowe Price Institutional Large-Cap Growth Fund | Returns after taxes on distributions and sale of fund shares	23.65%	15.79%	9.56%	Oct. 31, 2001
Russell 1000 Growth Index (reflects no deduction for fees, expenses, or taxes)	30.21%	17.33%	10.00%
Lipper Large-Cap Growth Funds Index	31.85%	15.90%	8.20%

Updated performance information is available through troweprice.com.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional Equity Funds, Inc.

Prospectus Date

rr_ProspectusDate

May 01, 2018

T. Rowe Price Institutional Large-Cap Growth Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. Rowe Price

Institutional Large-Cap Growth Fund

SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks to provide long-term capital appreciation through investments in common stocks of growth companies.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Fees and Expenses of the Fund

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 36.1% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

36.10%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

In taking a growth approach to stock selection, the fund will normally invest at least 80% of its net assets (including any borrowings for investment purposes) in the common stocks of large-cap companies. The fund defines a large-cap company as one whose market capitalization is larger than the median market capitalization of companies in the Russell 1000 Growth Index, a widely used benchmark of the largest U.S. growth stocks. As of December 31, 2017, the median market capitalization of companies in the Russell 1000 Growth Index was approximately $11.8 billion. The market capitalizations of the companies in the fund’s portfolio and the Russell index change over time; the fund will not automatically sell or cease to purchase stock of a company it already owns just because the company’s market capitalization falls below the median market capitalization of companies in the Russell index. The fund may at times invest significantly in certain sectors, such as the information technology sector.

We generally look for companies with an above-average rate of earnings and cash flow growth and a lucrative niche in the economy that gives them the ability to sustain earnings momentum even during times of slow economic growth. As growth investors, we believe that when a company increases its earnings faster than both inflation and the overall economy, the market will eventually reward it with a higher stock price.

The fund is “nondiversified,” meaning it may invest a greater portion of its assets in a single issuer and own more of the issuer’s voting securities than is permissible for a “diversified” fund.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

While most assets will typically be invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’s objective.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the stock market or because of factors that affect a particular company or industry.

Emerging markets risks The risks of foreign investing are heightened for securities of issuers in emerging market countries. Emerging market countries tend to have economic structures that are less diverse and mature, and political systems that are less stable, than those of developed countries. In addition to all of the risks of investing in foreign developed markets, emerging markets are more susceptible to governmental interference, local taxes being imposed on foreign investments, restrictions on gaining access to sales proceeds, and less liquid and less efficient trading markets.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Market capitalization risks Investing primarily in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment. Securities issued by large-cap companies tend to be less volatile than securities issued by smaller companies. However, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and may be unable to respond as quickly to competitive challenges.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the information technology sector. Companies in the information technology sector can be adversely affected by, among other things, intense competition, earnings disappointments, and rapid obsolescence of products and services due to technological innovations or changing consumer preferences.

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Risk Nondiversified Status [Text]

rr_RiskNondiversifiedStatus

Nondiversification risks As a nondiversified fund, the fund has the ability to invest a larger percentage of its assets in the securities of a smaller number of issuers than a diversified fund. As a result, poor performance by a single issuer could adversely affect fund performance more than if the fund were invested in a larger number of issuers. The fund’s share price can be expected to fluctuate more than that of a comparable diversified fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

troweprice.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

Institutional Large-Cap Growth Fund
Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	19.94%	Worst Quarter	12/31/08	-22.72%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns

Periods ended
December 31, 2017

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Large-Cap Growth Fund | T. Rowe Price Institutional Large-Cap Growth Fund

Risk/Return:

rr_RiskReturnAbstract

Management fees

rr_ManagementFeesOverAssets

0.55%

Other expenses

rr_OtherExpensesOverAssets

0.01%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.56%

1 year

rr_ExpenseExampleYear01

$ 57

3 years

rr_ExpenseExampleYear03

179

5 years

rr_ExpenseExampleYear05

313

10 years

rr_ExpenseExampleYear10

$ 701

2008

rr_AnnualReturn2008

(40.86%)

2009

rr_AnnualReturn2009

53.40%

2010

rr_AnnualReturn2010

16.29%

2011

rr_AnnualReturn2011

(1.40%)

2012

rr_AnnualReturn2012

17.55%

2013

rr_AnnualReturn2013

44.44%

2014

rr_AnnualReturn2014

8.72%

2015

rr_AnnualReturn2015

10.08%

2016

rr_AnnualReturn2016

2.85%

2017

rr_AnnualReturn2017

37.82%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

19.94%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(22.72%)

1 Year

rr_AverageAnnualReturnYear01

37.82%

5 Years

rr_AverageAnnualReturnYear05

19.63%

10 Years

rr_AverageAnnualReturnYear10

11.60%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2001

T. Rowe Price Institutional Large-Cap Growth Fund | Returns after taxes on distributions | T. Rowe Price Institutional Large-Cap Growth Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

35.00%

5 Years

rr_AverageAnnualReturnYear05

18.34%

10 Years

rr_AverageAnnualReturnYear10

10.98%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2001

T. Rowe Price Institutional Large-Cap Growth Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional Large-Cap Growth Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

23.65%

5 Years

rr_AverageAnnualReturnYear05

15.79%

10 Years

rr_AverageAnnualReturnYear10

9.56%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2001

T. Rowe Price Institutional Large-Cap Growth Fund | Russell 1000 Growth Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

30.21%

5 Years

rr_AverageAnnualReturnYear05

17.33%

10 Years

rr_AverageAnnualReturnYear10

10.00%

T. Rowe Price Institutional Large-Cap Growth Fund | Lipper Large-Cap Growth Funds Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

31.85%

5 Years

rr_AverageAnnualReturnYear05

15.90%

10 Years

rr_AverageAnnualReturnYear10

8.20%

XML

T. Rowe Price Institutional Large-Cap Value Fund

T. Rowe Price

Institutional Large-Cap Value Fund

SUMMARY

Investment Objective

The fund seeks to provide long-term capital appreciation by investing in common stocks believed to be undervalued.

Income is a secondary objective.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Annual Fund Operating Expenses	T. Rowe Price Institutional Large-Cap Value Fund T. Rowe Price Institutional Large-Cap Value Fund
Management fees	0.55%
Other expenses	0.02%
Total annual fund operating expenses	0.57%

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, 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:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Large-Cap Value Fund | T. Rowe Price Institutional Large-Cap Value Fund | USD ($)	58	183	318	714

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 30.8% of the average value of its portfolio.

Investments, Risks, and Performance

Principal Investment Strategies

In taking a value approach to investment selection, the fund will normally invest at least 80% of its net assets (including any borrowings for investment purposes) in securities of large-cap companies that the portfolio manager regards as undervalued. The fund defines a large-cap company as having a market capitalization that, at the time of purchase, is either (i) larger than the current median market capitalization of companies in the Russell 1000 Value Index or (ii) larger than the three year average median market capitalization of companies in the index as of December 31 of the three preceding years. The Russell 1000 Value Index is a widely used benchmark of the largest U.S. value stocks. As of December 31, 2017, the median market capitalization for the Russell 1000 Value Index was approximately $9.8 billion. The market capitalizations of the companies in the fund’s portfolio and the Russell index change over time; the fund will not automatically sell or cease to purchase stock of a company it owns just because the company’s market capitalization falls below these levels. The fund may also purchase stocks of smaller companies. The fund may at times invest significantly in certain sectors, such as the financials sector.

Our in-house research team seeks to identify companies that appear to be undervalued by various measures, and may be temporarily out of favor, but have good prospects for capital appreciation. In selecting investments, we generally look for one or more of the following:

• low price/earnings, price/book value, price/sales, or price/cash flow ratios relative to the Russell 1000 Value Index, the company’s peers, or its own historical norm;

• low stock price relative to a company’s underlying asset values;

• companies that may benefit from restructuring activity; and/or

• a sound balance sheet and other positive financial characteristics.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

While most assets will typically be invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’s objective.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of U.S. stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s value approach to investing could cause it to underperform other stock funds that employ a different investment style. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Market capitalization risks Investing primarily in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment. Securities issued by large-cap companies tend to be less volatile than securities issued by smaller companies. However, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and may be unable to respond as quickly to competitive challenges.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes or restrictions on gaining access to sales proceeds for foreign investors.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the financials sectors. Companies in the financials sector may be adversely impacted by, among other things, regulatory changes, economic conditions, interest rates, credit rating downgrades, and decreased liquidity in credit markets.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Institutional Large-Cap Value Fund
Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	20.20%	Worst Quarter	12/31/08	-23.77%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Average Annual Total Returns

Periods ended
December 31, 2017

Average Annual Total Returns - T. Rowe Price Institutional Large-Cap Value Fund	1 Year	5 Years	10 Years	Inception date
T. Rowe Price Institutional Large-Cap Value Fund	16.83%	14.75%	7.93%	Mar. 31, 2000
T. Rowe Price Institutional Large-Cap Value Fund | Returns after taxes on distributions	15.56%	13.74%	7.29%	Mar. 31, 2000
T. Rowe Price Institutional Large-Cap Value Fund | Returns after taxes on distributions and sale of fund shares	10.57%	11.74%	6.36%	Mar. 31, 2000
Russell 1000 Value Index (reflects no deduction for fees, expenses, or taxes)	13.66%	14.04%	7.10%
Lipper Large-Cap Value Funds Index	16.06%	13.99%	6.86%

Updated performance information is available through troweprice.com.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional Equity Funds, Inc.

Prospectus Date

rr_ProspectusDate

May 01, 2018

T. Rowe Price Institutional Large-Cap Value Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. Rowe Price

Institutional Large-Cap Value Fund

SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks to provide long-term capital appreciation by investing in common stocks believed to be undervalued.

Objective, Secondary [Text Block]

rr_ObjectiveSecondaryTextBlock

Income is a secondary objective.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Fees and Expenses of the Fund

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 30.8% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

30.80%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

In taking a value approach to investment selection, the fund will normally invest at least 80% of its net assets (including any borrowings for investment purposes) in securities of large-cap companies that the portfolio manager regards as undervalued. The fund defines a large-cap company as having a market capitalization that, at the time of purchase, is either (i) larger than the current median market capitalization of companies in the Russell 1000 Value Index or (ii) larger than the three year average median market capitalization of companies in the index as of December 31 of the three preceding years. The Russell 1000 Value Index is a widely used benchmark of the largest U.S. value stocks. As of December 31, 2017, the median market capitalization for the Russell 1000 Value Index was approximately $9.8 billion. The market capitalizations of the companies in the fund’s portfolio and the Russell index change over time; the fund will not automatically sell or cease to purchase stock of a company it owns just because the company’s market capitalization falls below these levels. The fund may also purchase stocks of smaller companies. The fund may at times invest significantly in certain sectors, such as the financials sector.

Our in-house research team seeks to identify companies that appear to be undervalued by various measures, and may be temporarily out of favor, but have good prospects for capital appreciation. In selecting investments, we generally look for one or more of the following:

• low price/earnings, price/book value, price/sales, or price/cash flow ratios relative to the Russell 1000 Value Index, the company’s peers, or its own historical norm;

• low stock price relative to a company’s underlying asset values;

• companies that may benefit from restructuring activity; and/or

• a sound balance sheet and other positive financial characteristics.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

While most assets will typically be invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’s objective.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of U.S. stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s value approach to investing could cause it to underperform other stock funds that employ a different investment style. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Market capitalization risks Investing primarily in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment. Securities issued by large-cap companies tend to be less volatile than securities issued by smaller companies. However, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and may be unable to respond as quickly to competitive challenges.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes or restrictions on gaining access to sales proceeds for foreign investors.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the financials sectors. Companies in the financials sector may be adversely impacted by, among other things, regulatory changes, economic conditions, interest rates, credit rating downgrades, and decreased liquidity in credit markets.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

troweprice.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

Institutional Large-Cap Value Fund
Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	20.20%	Worst Quarter	12/31/08	-23.77%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns

Periods ended
December 31, 2017

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Large-Cap Value Fund | T. Rowe Price Institutional Large-Cap Value Fund

Risk/Return:

rr_RiskReturnAbstract

Management fees

rr_ManagementFeesOverAssets

0.55%

Other expenses

rr_OtherExpensesOverAssets

0.02%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.57%

1 year

rr_ExpenseExampleYear01

$ 58

3 years

rr_ExpenseExampleYear03

183

5 years

rr_ExpenseExampleYear05

318

10 years

rr_ExpenseExampleYear10

$ 714

2008

rr_AnnualReturn2008

(36.17%)

2009

rr_AnnualReturn2009

28.09%

2010

rr_AnnualReturn2010

13.27%

2011

rr_AnnualReturn2011

(1.19%)

2012

rr_AnnualReturn2012

17.85%

2013

rr_AnnualReturn2013

33.98%

2014

rr_AnnualReturn2014

13.13%

2015

rr_AnnualReturn2015

(3.32%)

2016

rr_AnnualReturn2016

16.20%

2017

rr_AnnualReturn2017

16.83%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

20.20%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(23.77%)

1 Year

rr_AverageAnnualReturnYear01

16.83%

5 Years

rr_AverageAnnualReturnYear05

14.75%

10 Years

rr_AverageAnnualReturnYear10

7.93%

Inception date

rr_AverageAnnualReturnInceptionDate

Mar. 31, 2000

T. Rowe Price Institutional Large-Cap Value Fund | Returns after taxes on distributions | T. Rowe Price Institutional Large-Cap Value Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

15.56%

5 Years

rr_AverageAnnualReturnYear05

13.74%

10 Years

rr_AverageAnnualReturnYear10

7.29%

Inception date

rr_AverageAnnualReturnInceptionDate

Mar. 31, 2000

T. Rowe Price Institutional Large-Cap Value Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional Large-Cap Value Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

10.57%

5 Years

rr_AverageAnnualReturnYear05

11.74%

10 Years

rr_AverageAnnualReturnYear10

6.36%

Inception date

rr_AverageAnnualReturnInceptionDate

Mar. 31, 2000

T. Rowe Price Institutional Large-Cap Value Fund | Russell 1000 Value Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

13.66%

5 Years

rr_AverageAnnualReturnYear05

14.04%

10 Years

rr_AverageAnnualReturnYear10

7.10%

T. Rowe Price Institutional Large-Cap Value Fund | Lipper Large-Cap Value Funds Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

16.06%

5 Years

rr_AverageAnnualReturnYear05

13.99%

10 Years

rr_AverageAnnualReturnYear10

6.86%

XML

T. Rowe Price Institutional Mid-Cap Equity Growth Fund

T. Rowe Price

Institutional Mid-Cap Equity Growth Fund

SUMMARY

Investment Objective

The fund seeks to provide long-term capital appreciation by investing in mid-cap stocks with potential for above-average earnings growth.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Annual Fund Operating Expenses	T. Rowe Price Institutional Mid-Cap Equity Growth Fund T. Rowe Price Institutional Mid-Cap Equity Growth Fund
Management fees	0.60%
Other expenses	0.01%
Total annual fund operating expenses	0.61%

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, 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:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Mid-Cap Equity Growth Fund | T. Rowe Price Institutional Mid-Cap Equity Growth Fund | USD ($)	62	195	340	762

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 31.1% of the average value of its portfolio.

Investments, Risks, and Performance

Principal Investment Strategies

The fund will normally invest at least 80% of its net assets (including any borrowings for investment purposes) in a diversified portfolio of common stocks of mid-cap companies whose earnings T. Rowe Price expects to grow at a faster rate than the average company. The fund defines mid-cap companies as those whose market capitalization (number of shares outstanding multiplied by share price) falls within the range of either the S&P MidCap 400 Index or the Russell Midcap Growth Index. As of December 31, 2017, the market capitalization ranges for the S&P MidCap 400 Index and the Russell Midcap Growth Index were approximately $946 million to $13.1 billion, and $1.2 billion to $36.7 billion, respectively. The market capitalization of the companies in the fund’s portfolio and the S&P and Russell indices changes over time; the fund will not automatically sell or cease to purchase stock of a company it holds just because the company’s market capitalization grows or falls outside these ranges. The fund may at times invest significantly in certain sectors, such as the information technology sector.

As “growth” investors, T. Rowe Price believes that when a company’s earnings grow faster than both inflation and the overall economy, the market will eventually reward it with a higher stock price.

In selecting investments, we generally favor companies with one or more of the following:

• proven products or services;

• a record of above-average earnings growth;

• demonstrated potential to sustain earnings growth;

• connection to an industry experiencing increasing demand; or

• stock prices that appear to undervalue their growth prospects.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

While most assets will typically be invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’s objective.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of U.S. stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Mid-cap stock risks Investing primarily in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment. Because the fund invests primarily in securities issued by mid-cap companies, it is likely to be more volatile than a fund that focuses on securities issued by large companies. Medium-sized companies may have less seasoned management, narrower product lines, and less capital reserves and liquidity than larger companies, and are therefore more sensitive to economic, market, and industry changes.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes or restrictions on gaining access to sales proceeds for foreign investors.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the information technology sector. Companies in the information technology sector can be adversely affected by, among other things, intense competition, earnings disappointments, and rapid obsolescence of products and services due to technological innovations or changing consumer preferences.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Institutional Mid-Cap Equity Growth Fund
Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	9/30/09	19.76%	Worst Quarter	12/31/08	-25.87%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Average Annual Total Returns

Periods ended
December 31, 2017

Average Annual Total Returns - T. Rowe Price Institutional Mid-Cap Equity Growth Fund	1 Year	5 Years	10 Years	Inception date
T. Rowe Price Institutional Mid-Cap Equity Growth Fund	26.02%	17.73%	11.16%	Jul. 31, 1996
T. Rowe Price Institutional Mid-Cap Equity Growth Fund | Returns after taxes on distributions	24.24%	16.39%	10.39%	Jul. 31, 1996
T. Rowe Price Institutional Mid-Cap Equity Growth Fund | Returns after taxes on distributions and sale of fund shares	16.18%	14.13%	9.09%	Jul. 31, 1996
Russell Midcap Growth Index (reflects no deduction for fees, expenses, or taxes)	25.27%	15.30%	9.10%
Lipper Mid-Cap Growth Funds Index	25.90%	14.31%	7.71%

Updated performance information is available through troweprice.com.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional Equity Funds, Inc.

Prospectus Date

rr_ProspectusDate

May 01, 2018

T. Rowe Price Institutional Mid-Cap Equity Growth Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. Rowe Price

Institutional Mid-Cap Equity Growth Fund

SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks to provide long-term capital appreciation by investing in mid-cap stocks with potential for above-average earnings growth.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Fees and Expenses of the Fund

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 31.1% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

31.10%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund will normally invest at least 80% of its net assets (including any borrowings for investment purposes) in a diversified portfolio of common stocks of mid-cap companies whose earnings T. Rowe Price expects to grow at a faster rate than the average company. The fund defines mid-cap companies as those whose market capitalization (number of shares outstanding multiplied by share price) falls within the range of either the S&P MidCap 400 Index or the Russell Midcap Growth Index. As of December 31, 2017, the market capitalization ranges for the S&P MidCap 400 Index and the Russell Midcap Growth Index were approximately $946 million to $13.1 billion, and $1.2 billion to $36.7 billion, respectively. The market capitalization of the companies in the fund’s portfolio and the S&P and Russell indices changes over time; the fund will not automatically sell or cease to purchase stock of a company it holds just because the company’s market capitalization grows or falls outside these ranges. The fund may at times invest significantly in certain sectors, such as the information technology sector.

As “growth” investors, T. Rowe Price believes that when a company’s earnings grow faster than both inflation and the overall economy, the market will eventually reward it with a higher stock price.

In selecting investments, we generally favor companies with one or more of the following:

• proven products or services;

• a record of above-average earnings growth;

• demonstrated potential to sustain earnings growth;

• connection to an industry experiencing increasing demand; or

• stock prices that appear to undervalue their growth prospects.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

While most assets will typically be invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’s objective.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of U.S. stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Mid-cap stock risks Investing primarily in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment. Because the fund invests primarily in securities issued by mid-cap companies, it is likely to be more volatile than a fund that focuses on securities issued by large companies. Medium-sized companies may have less seasoned management, narrower product lines, and less capital reserves and liquidity than larger companies, and are therefore more sensitive to economic, market, and industry changes.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. The fund’s growth approach to investing could cause it to underperform other stock funds that employ a different investment style. Growth stocks tend to be more volatile than certain other types of stocks, and their prices may fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividends that can help cushion its share price in a declining market.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes or restrictions on gaining access to sales proceeds for foreign investors.

Sector concentration risks At times, the fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. For example, the fund may have a significant portion of its assets invested in securities of companies in the information technology sector. Companies in the information technology sector can be adversely affected by, among other things, intense competition, earnings disappointments, and rapid obsolescence of products and services due to technological innovations or changing consumer preferences.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

troweprice.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

Institutional Mid-Cap Equity Growth Fund
Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	9/30/09	19.76%	Worst Quarter	12/31/08	-25.87%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns

Periods ended
December 31, 2017

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Mid-Cap Equity Growth Fund | T. Rowe Price Institutional Mid-Cap Equity Growth Fund

Risk/Return:

rr_RiskReturnAbstract

Management fees

rr_ManagementFeesOverAssets

0.60%

Other expenses

rr_OtherExpensesOverAssets

0.01%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.61%

1 year

rr_ExpenseExampleYear01

$ 62

3 years

rr_ExpenseExampleYear03

195

5 years

rr_ExpenseExampleYear05

340

10 years

rr_ExpenseExampleYear10

$ 762

2008

rr_AnnualReturn2008

(40.59%)

2009

rr_AnnualReturn2009

46.78%

2010

rr_AnnualReturn2010

29.24%

2011

rr_AnnualReturn2011

(1.28%)

2012

rr_AnnualReturn2012

14.50%

2013

rr_AnnualReturn2013

37.89%

2014

rr_AnnualReturn2014

13.79%

2015

rr_AnnualReturn2015

6.94%

2016

rr_AnnualReturn2016

6.94%

2017

rr_AnnualReturn2017

26.02%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

19.76%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(25.87%)

1 Year

rr_AverageAnnualReturnYear01

26.02%

5 Years

rr_AverageAnnualReturnYear05

17.73%

10 Years

rr_AverageAnnualReturnYear10

11.16%

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 31, 1996

T. Rowe Price Institutional Mid-Cap Equity Growth Fund | Returns after taxes on distributions | T. Rowe Price Institutional Mid-Cap Equity Growth Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

24.24%

5 Years

rr_AverageAnnualReturnYear05

16.39%

10 Years

rr_AverageAnnualReturnYear10

10.39%

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 31, 1996

T. Rowe Price Institutional Mid-Cap Equity Growth Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional Mid-Cap Equity Growth Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

16.18%

5 Years

rr_AverageAnnualReturnYear05

14.13%

10 Years

rr_AverageAnnualReturnYear10

9.09%

Inception date

rr_AverageAnnualReturnInceptionDate

Jul. 31, 1996

T. Rowe Price Institutional Mid-Cap Equity Growth Fund | Russell Midcap Growth Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

25.27%

5 Years

rr_AverageAnnualReturnYear05

15.30%

10 Years

rr_AverageAnnualReturnYear10

9.10%

T. Rowe Price Institutional Mid-Cap Equity Growth Fund | Lipper Mid-Cap Growth Funds Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

25.90%

5 Years

rr_AverageAnnualReturnYear05

14.31%

10 Years

rr_AverageAnnualReturnYear10

7.71%

XML

T. Rowe Price Institutional Small-Cap Stock Fund

T. Rowe Price

Institutional Small-Cap

Stock Fund

SUMMARY

Investment Objective

The fund seeks to provide long-term capital growth by investing primarily in stocks of small companies.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Annual Fund Operating Expenses	T. Rowe Price Institutional Small-Cap Stock Fund T. Rowe Price Institutional Small-Cap Stock Fund
Management fees	0.65%
Other expenses	0.01%
Total annual fund operating expenses	0.66%

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, 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:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional Small-Cap Stock Fund | T. Rowe Price Institutional Small-Cap Stock Fund | USD ($)	67	211	368	822

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 41.6% of the average value of its portfolio.

Investments, Risks, and Performance

Principal Investment Strategies

The fund will normally invest at least 80% of its net assets (including any borrowings for investment purposes) in stocks of small companies. The fund defines a small company as one whose market capitalization falls (i) within or below the current range of companies in either the Russell 2000^® Index or the S&P SmallCap 600 Index or (ii) below the three-year average maximum market cap of companies in either index as of December 31 of the three preceding years. The Russell 2000 and S&P SmallCap 600 Indices are widely used benchmarks for tracking small-cap stock performance. As of December 31, 2017, the market capitalization ranges for the Russell 2000 Index and the S&P SmallCap 600 Index were approximately $22.7 million to $9.4 billion, and $95.5 million to $24.4 billion, respectively. The market capitalizations of the companies in the fund’s portfolio and the S&P and Russell indexes change over time; the fund will not automatically sell or cease to purchase stock of a company it already owns just because the company’s market capitalization grows or falls outside this range. The fund may, on occasion, purchase companies with a market capitalization above the ranges. When choosing stocks, we generally look for one or more of the following characteristics:

• capable management;

• attractive business niches;

• pricing flexibility;

• sound financial and accounting practices;

• a potential or demonstrated ability to grow revenues, earnings, and cash flow consistently; and

• the potential for a catalyst (such as increased investor attention, asset sales, strong business prospects, or a change in management) to cause the stock’s price to rise.

Holdings will be widely diversified by industry and issuer, and stock selection may reflect either a growth or value investment approach. For example, we may look for a company whose price/earnings ratio is attractive relative to the underlying earnings growth rate. A value stock would be one where the stock price appears undervalued in relation to earnings, projected cash flow, or asset value per share.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

While most assets will typically be invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’s objective.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of U.S. stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. Because the fund may hold stocks with either growth or value characteristics, it could underperform other stock funds that take a strictly growth or value approach to investing when one style is currently in favor. Growth stocks tend to be more volatile than the overall stock market and can have sharp price declines as a result of earnings disappointments. Value stocks carry the risk that the market will not recognize their intrinsic value or that they are actually appropriately priced at a low level.

Small-cap stock risks Investing primarily in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment. Because the fund invests primarily in securities issued by small-cap companies, it is likely to be more volatile than a fund that focuses on securities issued by larger companies. Small companies often have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies. In addition, smaller companies are typically more sensitive to changes in overall economic conditions and their securities may be difficult to trade.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes or restrictions on gaining access to sales proceeds for foreign investors.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Institutional Small-Cap Stock Fund
Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	21.71%	Worst Quarter	12/31/08	-23.90%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Average Annual Total Returns

Periods ended
December 31, 2017

Average Annual Total Returns - T. Rowe Price Institutional Small-Cap Stock Fund	1 Year	5 Years	10 Years	Inception date
T. Rowe Price Institutional Small-Cap Stock Fund	15.45%	14.83%	11.39%	Mar. 31, 2000
T. Rowe Price Institutional Small-Cap Stock Fund | Returns after taxes on distributions	13.53%	13.48%	10.48%	Mar. 31, 2000
T. Rowe Price Institutional Small-Cap Stock Fund | Returns after taxes on distributions and sale of fund shares	9.90%	11.67%	9.28%	Mar. 31, 2000
Russell 2000 Index (reflects no deduction for fees, expenses, or taxes)	14.65%	14.12%	8.71%
S&P SmallCap 600 Index (reflects no deduction for fees, expenses, or taxes)	13.23%	15.99%	10.43%
Lipper Small-Cap Core Funds Index	13.95%	13.64%	8.69%

Updated performance information is available through troweprice.com.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional Equity Funds, Inc.

Prospectus Date

rr_ProspectusDate

May 01, 2018

T. Rowe Price Institutional Small-Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. Rowe Price

Institutional Small-Cap

Stock Fund

SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks to provide long-term capital growth by investing primarily in stocks of small companies.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Fees and Expenses of the Fund

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 41.6% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

41.60%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The fund will normally invest at least 80% of its net assets (including any borrowings for investment purposes) in stocks of small companies. The fund defines a small company as one whose market capitalization falls (i) within or below the current range of companies in either the Russell 2000^® Index or the S&P SmallCap 600 Index or (ii) below the three-year average maximum market cap of companies in either index as of December 31 of the three preceding years. The Russell 2000 and S&P SmallCap 600 Indices are widely used benchmarks for tracking small-cap stock performance. As of December 31, 2017, the market capitalization ranges for the Russell 2000 Index and the S&P SmallCap 600 Index were approximately $22.7 million to $9.4 billion, and $95.5 million to $24.4 billion, respectively. The market capitalizations of the companies in the fund’s portfolio and the S&P and Russell indexes change over time; the fund will not automatically sell or cease to purchase stock of a company it already owns just because the company’s market capitalization grows or falls outside this range. The fund may, on occasion, purchase companies with a market capitalization above the ranges. When choosing stocks, we generally look for one or more of the following characteristics:

• capable management;

• attractive business niches;

• pricing flexibility;

• sound financial and accounting practices;

• a potential or demonstrated ability to grow revenues, earnings, and cash flow consistently; and

• the potential for a catalyst (such as increased investor attention, asset sales, strong business prospects, or a change in management) to cause the stock’s price to rise.

Holdings will be widely diversified by industry and issuer, and stock selection may reflect either a growth or value investment approach. For example, we may look for a company whose price/earnings ratio is attractive relative to the underlying earnings growth rate. A value stock would be one where the stock price appears undervalued in relation to earnings, projected cash flow, or asset value per share.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

While most assets will typically be invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’s objective.

The fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of U.S. stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. Because the fund may hold stocks with either growth or value characteristics, it could underperform other stock funds that take a strictly growth or value approach to investing when one style is currently in favor. Growth stocks tend to be more volatile than the overall stock market and can have sharp price declines as a result of earnings disappointments. Value stocks carry the risk that the market will not recognize their intrinsic value or that they are actually appropriately priced at a low level.

Small-cap stock risks Investing primarily in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment. Because the fund invests primarily in securities issued by small-cap companies, it is likely to be more volatile than a fund that focuses on securities issued by larger companies. Small companies often have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies. In addition, smaller companies are typically more sensitive to changes in overall economic conditions and their securities may be difficult to trade.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar. These risks are heightened for the fund’s investments in emerging markets, which are more susceptible to governmental interference, less efficient trading markets, and the imposition of local taxes or restrictions on gaining access to sales proceeds for foreign investors.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

troweprice.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

Institutional Small-Cap Stock Fund
Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	21.71%	Worst Quarter	12/31/08	-23.90%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns

Periods ended
December 31, 2017

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional Small-Cap Stock Fund | T. Rowe Price Institutional Small-Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

Management fees

rr_ManagementFeesOverAssets

0.65%

Other expenses

rr_OtherExpensesOverAssets

0.01%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.66%

1 year

rr_ExpenseExampleYear01

$ 67

3 years

rr_ExpenseExampleYear03

211

5 years

rr_ExpenseExampleYear05

368

10 years

rr_ExpenseExampleYear10

$ 822

2008

rr_AnnualReturn2008

(33.10%)

2009

rr_AnnualReturn2009

39.22%

2010

rr_AnnualReturn2010

32.96%

2011

rr_AnnualReturn2011

0.22%

2012

rr_AnnualReturn2012

18.68%

2013

rr_AnnualReturn2013

39.56%

2014

rr_AnnualReturn2014

7.42%

2015

rr_AnnualReturn2015

(3.07%)

2016

rr_AnnualReturn2016

19.00%

2017

rr_AnnualReturn2017

15.45%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

21.71%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(23.90%)

1 Year

rr_AverageAnnualReturnYear01

15.45%

5 Years

rr_AverageAnnualReturnYear05

14.83%

10 Years

rr_AverageAnnualReturnYear10

11.39%

Inception date

rr_AverageAnnualReturnInceptionDate

Mar. 31, 2000

T. Rowe Price Institutional Small-Cap Stock Fund | Returns after taxes on distributions | T. Rowe Price Institutional Small-Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

13.53%

5 Years

rr_AverageAnnualReturnYear05

13.48%

10 Years

rr_AverageAnnualReturnYear10

10.48%

Inception date

rr_AverageAnnualReturnInceptionDate

Mar. 31, 2000

T. Rowe Price Institutional Small-Cap Stock Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional Small-Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

9.90%

5 Years

rr_AverageAnnualReturnYear05

11.67%

10 Years

rr_AverageAnnualReturnYear10

9.28%

Inception date

rr_AverageAnnualReturnInceptionDate

Mar. 31, 2000

T. Rowe Price Institutional Small-Cap Stock Fund | Russell 2000 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

14.65%

5 Years

rr_AverageAnnualReturnYear05

14.12%

10 Years

rr_AverageAnnualReturnYear10

8.71%

T. Rowe Price Institutional Small-Cap Stock Fund | S&P SmallCap 600 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

13.23%

5 Years

rr_AverageAnnualReturnYear05

15.99%

10 Years

rr_AverageAnnualReturnYear10

10.43%

T. Rowe Price Institutional Small-Cap Stock Fund | Lipper Small-Cap Core Funds Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

13.95%

5 Years

rr_AverageAnnualReturnYear05

13.64%

10 Years

rr_AverageAnnualReturnYear10

8.69%

XML

T. Rowe Price Institutional U.S. Structured Research Fund

T. Rowe Price

Institutional U.S. Structured

Research Fund

SUMMARY

Investment Objective

The fund seeks to provide long-term capital growth by investing primarily in U.S. common stocks.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Annual Fund Operating Expenses	T. Rowe Price Institutional U.S. Structured Research Fund T. Rowe Price Institutional U.S. Structured Research Fund
Management fees	0.50%
Other expenses	0.05%
Total annual fund operating expenses	0.55%

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, 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:

Expense Example	1 year	3 years	5 years	10 years
T. Rowe Price Institutional U.S. Structured Research Fund | T. Rowe Price Institutional U.S. Structured Research Fund | USD ($)	56	176	307	689

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 36.4% of the average value of its portfolio.

Investments, Risks, and Performance

Principal Investment Strategies

The strategy attempts to create a portfolio with similar characteristics to the Standard & Poor’s 500 Stock Index^® (S&P 500 Index) with the potential to provide excess returns relative to the Index. The fund uses a disciplined portfolio construction process whereby it weights each sector and industry approximately the same as the S&P 500 Index. Within each sector and industry, the weighting of individual fund holdings can vary significantly from their weighting within the S&P 500 Index. The fund, which may be considered an “enhanced index” fund, attempts to outperform the S&P 500 Index by overweighting those stocks that are viewed favorably relative to their weighting in the Index, and underweighting or avoiding those stocks that are viewed negatively. The fund may also purchase stocks that are not in the S&P 500 Index, but at least 80% of the fund’s total assets will normally be invested in stocks that are in the S&P 500 Index at the time of purchase.

A portfolio oversight team is responsible for the overall structure of the fund and for developing rules for portfolio construction. The portfolio oversight team seeks to take advantage of T. Rowe Price’s fundamental research by assigning equity analysts to select stocks for the fund within industries where they have focused expertise. The equity analysts are directly responsible for selecting stocks and determining the stocks’ weights within their industry-specific portfolios. The analysts actively select stocks from the industries they cover based on fundamental research, which considers various factors such as the quality of a company’s management team and its business franchise, earnings growth potential of a company and its market sector, and valuation. The fund’s portfolio oversight team maintains responsibility for evaluating the performance of the overall portfolio and the analysts’ stock selections, tracking and aligning the fund’s risk characteristics with those of the S&P 500 Index, monitoring the portfolio’s exposures to industries and sectors, managing cash flows into and out of the fund, and ensuring overall compliance by the analysts with the fund’s portfolio construction principles. The portfolio oversight team is responsible for selecting stocks that meet the fund’s investment criteria, but have not yet been assigned to an analyst.

Because the fund is designed to have similar characteristics to the S&P 500 Index, there is expected to be a relatively close correlation between the fund’s performance and the performance of the Index in both rising and falling markets. However, when compared to a fund that follows a strict indexing strategy, there is a much greater chance that the fund’s performance will deviate from the Index (referred to as “tracking error”) and the potential for higher portfolio turnover, which increases the possibility of taxable distributions to shareholders and results in higher transaction costs to the fund.

The fund will generally remain fully invested (less than 5% in cash reserves) and seeks to be sector neutral when compared to the S&P 500 Index. While the majority of assets will be invested in large-capitalization U.S. common stocks, small- and mid-capitalization and foreign stocks may also be purchased in keeping with fund objectives. Securities may be sold for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities. The fund may at times invest significantly in certain sectors, such as the information technology sector.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of U.S. stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. Because the fund may hold stocks with either growth or value characteristics, it could underperform other stock funds that take a strictly growth or value approach to investing when one style is currently in favor. Growth stocks tend to be more volatile than the overall stock market and can have sharp price declines as a result of earnings disappointments. Value stocks carry the risk that the market will not recognize their intrinsic value or that they are actually appropriately priced at a low level.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Institutional U.S. Structured Research Fund
Calendar Year Returns

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	16.73%	Worst Quarter	12/31/08	-21.79%

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Average Annual Total Returns

Periods ended
December 31, 2017

Average Annual Total Returns - T. Rowe Price Institutional U.S. Structured Research Fund	1 Year	5 Years	10 Years	Inception date
T. Rowe Price Institutional U.S. Structured Research Fund	23.81%	15.99%	8.77%	Oct. 31, 2007
T. Rowe Price Institutional U.S. Structured Research Fund | Returns after taxes on distributions	20.26%	13.52%	7.48%	Oct. 31, 2007
T. Rowe Price Institutional U.S. Structured Research Fund | Returns after taxes on distributions and sale of fund shares	16.24%	12.48%	6.94%	Oct. 31, 2007
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	21.83%	15.79%	8.50%
Lipper Large-Cap Core Funds Index	20.90%	14.63%	7.58%

Updated performance information is available through troweprice.com.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Institutional Equity Funds, Inc.

Prospectus Date

rr_ProspectusDate

May 01, 2018

T. Rowe Price Institutional U.S. Structured Research Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

T. Rowe Price

Institutional U.S. Structured

Research Fund

SUMMARY

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks to provide long-term capital growth by investing primarily in U.S. common stocks.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Fees and Expenses of the Fund

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 the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund’s performance. During the most recent fiscal year, the fund’s portfolio turnover rate was 36.4% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

36.40%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Investments, Risks, and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The strategy attempts to create a portfolio with similar characteristics to the Standard & Poor’s 500 Stock Index^® (S&P 500 Index) with the potential to provide excess returns relative to the Index. The fund uses a disciplined portfolio construction process whereby it weights each sector and industry approximately the same as the S&P 500 Index. Within each sector and industry, the weighting of individual fund holdings can vary significantly from their weighting within the S&P 500 Index. The fund, which may be considered an “enhanced index” fund, attempts to outperform the S&P 500 Index by overweighting those stocks that are viewed favorably relative to their weighting in the Index, and underweighting or avoiding those stocks that are viewed negatively. The fund may also purchase stocks that are not in the S&P 500 Index, but at least 80% of the fund’s total assets will normally be invested in stocks that are in the S&P 500 Index at the time of purchase.

A portfolio oversight team is responsible for the overall structure of the fund and for developing rules for portfolio construction. The portfolio oversight team seeks to take advantage of T. Rowe Price’s fundamental research by assigning equity analysts to select stocks for the fund within industries where they have focused expertise. The equity analysts are directly responsible for selecting stocks and determining the stocks’ weights within their industry-specific portfolios. The analysts actively select stocks from the industries they cover based on fundamental research, which considers various factors such as the quality of a company’s management team and its business franchise, earnings growth potential of a company and its market sector, and valuation. The fund’s portfolio oversight team maintains responsibility for evaluating the performance of the overall portfolio and the analysts’ stock selections, tracking and aligning the fund’s risk characteristics with those of the S&P 500 Index, monitoring the portfolio’s exposures to industries and sectors, managing cash flows into and out of the fund, and ensuring overall compliance by the analysts with the fund’s portfolio construction principles. The portfolio oversight team is responsible for selecting stocks that meet the fund’s investment criteria, but have not yet been assigned to an analyst.

Because the fund is designed to have similar characteristics to the S&P 500 Index, there is expected to be a relatively close correlation between the fund’s performance and the performance of the Index in both rising and falling markets. However, when compared to a fund that follows a strict indexing strategy, there is a much greater chance that the fund’s performance will deviate from the Index (referred to as “tracking error”) and the potential for higher portfolio turnover, which increases the possibility of taxable distributions to shareholders and results in higher transaction costs to the fund.

The fund will generally remain fully invested (less than 5% in cash reserves) and seeks to be sector neutral when compared to the S&P 500 Index. While the majority of assets will be invested in large-capitalization U.S. common stocks, small- and mid-capitalization and foreign stocks may also be purchased in keeping with fund objectives. Securities may be sold for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities. The fund may at times invest significantly in certain sectors, such as the information technology sector.

In pursuing its investment objective, the fund has the discretion to deviate from its normal investment criteria. These situations might arise when the fund’s adviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Active management risks The investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies if the fund’s overall investment selections or strategies fail to produce the intended results.

Risks of U.S. stock investing Stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Investment style risks Different investment styles tend to shift in and out of favor depending on market conditions and investor sentiment. Because the fund may hold stocks with either growth or value characteristics, it could underperform other stock funds that take a strictly growth or value approach to investing when one style is currently in favor. Growth stocks tend to be more volatile than the overall stock market and can have sharp price declines as a result of earnings disappointments. Value stocks carry the risk that the market will not recognize their intrinsic value or that they are actually appropriately priced at a low level.

Market capitalization risks The fund’s focus on large companies subjects the fund to the risks that larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods, and that they may be less capable of responding quickly to competitive challenges and industry changes. Because the fund may invest in companies of any size, its share price could be more volatile than a fund that invests only in large companies. Small and medium-sized companies typically have less experienced management, narrower product lines, more limited financial resources, and less publicly available information than larger companies.

Foreign investing risks The fund’s investments in foreign securities may be adversely affected by local, political, social, and economic conditions overseas, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Risk Lose Money [Text]

rr_RiskLoseMoney

The fund’s share price fluctuates, which means you could lose money by investing in the fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following performance information provides some indication of the risks of investing in the fund.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund.

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

troweprice.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

Institutional U.S. Structured Research Fund
Calendar Year Returns

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	16.73%	Worst Quarter	12/31/08	-21.79%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns

Periods ended
December 31, 2017

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for the fund, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Updated performance information is available through troweprice.com.

T. Rowe Price Institutional U.S. Structured Research Fund | T. Rowe Price Institutional U.S. Structured Research Fund

Risk/Return:

rr_RiskReturnAbstract

Management fees

rr_ManagementFeesOverAssets

0.50%

Other expenses

rr_OtherExpensesOverAssets

0.05%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.55%

1 year

rr_ExpenseExampleYear01

$ 56

3 years

rr_ExpenseExampleYear03

176

5 years

rr_ExpenseExampleYear05

307

10 years

rr_ExpenseExampleYear10

$ 689

2008

rr_AnnualReturn2008

(36.32%)

2009

rr_AnnualReturn2009

29.42%

2010

rr_AnnualReturn2010

13.60%

2011

rr_AnnualReturn2011

1.42%

2012

rr_AnnualReturn2012

16.22%

2013

rr_AnnualReturn2013

32.86%

2014

rr_AnnualReturn2014

12.35%

2015

rr_AnnualReturn2015

2.94%

2016

rr_AnnualReturn2016

10.37%

2017

rr_AnnualReturn2017

23.81%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

16.73%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(21.79%)

1 Year

rr_AverageAnnualReturnYear01

23.81%

5 Years

rr_AverageAnnualReturnYear05

15.99%

10 Years

rr_AverageAnnualReturnYear10

8.77%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2007

T. Rowe Price Institutional U.S. Structured Research Fund | Returns after taxes on distributions | T. Rowe Price Institutional U.S. Structured Research Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

20.26%

5 Years

rr_AverageAnnualReturnYear05

13.52%

10 Years

rr_AverageAnnualReturnYear10

7.48%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2007

T. Rowe Price Institutional U.S. Structured Research Fund | Returns after taxes on distributions and sale of fund shares | T. Rowe Price Institutional U.S. Structured Research Fund

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

16.24%

5 Years

rr_AverageAnnualReturnYear05

12.48%

10 Years

rr_AverageAnnualReturnYear10

6.94%

Inception date

rr_AverageAnnualReturnInceptionDate

Oct. 31, 2007

T. Rowe Price Institutional U.S. Structured Research Fund | S&P 500 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

21.83%

5 Years

rr_AverageAnnualReturnYear05

15.79%

10 Years

rr_AverageAnnualReturnYear10

8.50%

T. Rowe Price Institutional U.S. Structured Research Fund | Lipper Large-Cap Core Funds Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

20.90%

5 Years

rr_AverageAnnualReturnYear05

14.63%

10 Years

rr_AverageAnnualReturnYear10

7.58%

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	T. Rowe Price Institutional Equity Funds, Inc.
Prospectus Date	rr_ProspectusDate	May 01, 2018
Document Creation Date	dei_DocumentCreationDate	Apr. 26, 2018