<PAGE>
 
                                                      Exhibit (3)-3
                                                      Unicom Corporation
                                                      Form 10-Q File No. 1-11375








                              UNICOM CORPORATION

                                    BY-LAWS

                          EFFECTIVE JANUARY 28, 1994
                              AS AMENDED THROUGH
                                        
                                 MAY 28, 1998



<PAGE>
 
<TABLE>
<CAPTION>
 
 
                                  CONTENTS
 
                                                                 Page
                                                                Number
                                                                ------
<S>              <C>                                          <C>
ARTICLE I.       Stock......................................       1
 
ARTICLE II.      Meetings of Shareholders...................       3
 
ARTICLE III.     Board of Directors.........................       9
 
ARTICLE IV.      Committees of the Board of Directors.......      11
 
ARTICLE V.       Officers...................................      15
 
ARTICLE VI.      Indemnification............................      20
 
ARTICLE VII.     Miscellaneous..............................      21
 
ARTICLE VIII.    Alteration, Amendment or Repeal of By-Laws.      22
 
</TABLE>
<PAGE>
 
                              UNICOM CORPORATION

                                    BY-LAWS

                               ----------------

                                  ARTICLE I.

                                    STOCK.

  SECTION 1.  Each holder of fully paid stock shall be entitled to a
certificate or certificates of stock stating the number and class of shares, and
the designation of the series, if any, which such certificate represents. All
certificates of stock shall at the time of their issuance be signed either
manually or by facsimile signature by the Chairman, the President or a Vice
President and by the Secretary or an Assistant Secretary. All certificates of
stock shall be sealed with the seal of the Company or a facsimile of such seal,
shall be countersigned either manually or by facsimile signature by a Transfer
Agent and shall be authenticated by manual signature and registered by a
Registrar. The Board of Directors shall appoint one or more Transfer Agents,
none of whom shall be officers of the Company authorized to sign certificates of
stock, and one or more Registrars, each of which Registrars shall be a bank or
trust company. Certificates of stock shall not be valid until countersigned by a
Transfer Agent and authenticated and registered by a Registrar in the manner
provided by the Board of Directors.
  
  SECTION 2.  Shares of stock shall be transferable only on the books of the
Company and, except as hereinafter provided or as otherwise required by law,
shall be transferred only upon proper endorsement and surrender of the
certificates issued therefor.  If an outstanding certificate of stock shall be
lost, destroyed or stolen, the holder thereof may have a new certificate upon
producing evidence satisfactory to the Board of Directors of such loss,
destruction or theft, and upon furnishing to the Company, the Transfer Agents
and the Registrars a bond of indemnity deemed sufficient by the Board of
Directors against claims under the outstanding certificate.

                                      -1-

<PAGE>
 
     SECTION 3.  The certificates for each class or series of stock shall be
numbered and issued in consecutive order and a record shall be kept of the name
and address of the person to whom each certificate is issued, the number of
shares represented by the certificate and the number and date of the
certificate.  All certificates exchanged or returned to the Company or the
Transfer Agent for transfer shall be canceled and filed.

  SECTION 4.  For the purpose of determining shareholders entitled to notice of
or to vote at any meeting of shareholders, or shareholders entitled to receive
payment of any dividend, or in order to make a determination of shareholders for
any other proper purpose, the Board of Directors may fix in advance a date as
the record date for any such determination of shareholders, such date in any
case to be not more than sixty days and, for a meeting of shareholders, not less
than ten days, or in the case of a merger, consolidation, share exchange,
dissolution or sale, lease or exchange of assets, not less than twenty days,
immediately preceding such meeting.

  SECTION 5.  If any subscription for stock in the Company or any installment of
such subscription shall be unpaid when due, as the Board of Directors shall have
determined the time for payment, and shall continue unpaid for twenty days after
demand for the amount due, made either in person or by written notice duly
mailed to the last address, as it appears on the records of the Company, of the
subscriber or other person by whom the subscription or installment shall be
payable, the stock or subscription upon which payment shall be so due shall,
upon the expiration of said twenty days, become and be forfeited to the Company
without further action, demand or notice, and such stock or subscription may be
sold at public sale, subject to payment of the amount due and unpaid, plus all
costs and expenses incurred by the Company in that connection, at a time and
place to be stated in a written notice to be mailed to the recorded address of
the delinquent subscriber or other person in default on the subscription at
least ten days prior to the time fixed for such sale; provided, that the excess
of proceeds of such sale realized over the amount due and unpaid on said stock
or subscription shall be paid to the delinquent subscriber of other person in
default on the subscription, or to his or her legal representative; and,
provided further, that no forfeiture of stock, or of any amounts paid upon a
subscription therefor, 

                                      -2-
<PAGE>
 
shall be declared as against the estate of any decedent before distribution
shall have been made of the estate.

  The foregoing provisions for the forfeiture and sale of stock or
subscriptions shall not exclude any other remedy which may lawfully be
enforceable at any time, by forfeiture of stock or of amounts theretofore paid
or otherwise, against any person for nonpayment of a subscription or of any
installment thereof.

  SECTION 6.  Transfers of shares shall be made only on the books of the Company
by the registered holder thereof or by his or her legal representative, who
shall furnish proper evidence of authority to transfer, or by his or her
attorney or successor thereunto authorized by power of attorney or by documents
duly executed and filed with the Secretary or Transfer Agent of the Company, and
upon surrender for cancellation of the certificate for such shares.  The person
in whose name shares stand on the books of the Company shall be deemed the owner
thereof for all purposes as regards the Company.

  SECTION 7.  The Company shall be entitled to treat the holder of record of any
share or shares of stock as the holder in fact thereof and accordingly, shall
not be bound to recognize any equitable or other claim to or interest in such
share or shares on the part of any other person, whether or not it shall have
express or other notice thereof, except as otherwise provided by the laws of the
State of Illinois.

                                  ARTICLE II.

                           MEETINGS OF SHAREHOLDERS.

  SECTION 1.  (a) The regular annual meeting of the shareholders of the Company
for the election of Directors and for the transaction of such other business as
may properly come before the meeting shall be held on such day in April or May
of each year as the Board of Directors may by resolution determine.  Each such
regular annual meeting and each special meeting of the shareholders shall be
held at such place as may be fixed by the Board of Directors and at such hour as
the Board of Directors shall order.

  (b) Only such business shall be conducted at an annual meeting of shareholders
as shall have been properly brought 

                                      -3-
<PAGE>
 
before the meeting. For business to be properly brought before the meeting, it
must be: (i) authorized by the Board of Directors and specified in the notice,
or a supplemental notice, of the meeting, (ii) otherwise be brought before the
meeting by or at the direction of the Board of Directors or (iii) otherwise
properly brought before the meeting by a shareholder of the Company who is a
shareholder of record at the time of giving of the notice provided for in this
Section, who shall be entitled to vote at such annual meeting and who complies
with the procedures set forth in this Section 1(b). For business to be properly
brought before an annual meeting by a shareholder, the shareholder must have
given timely notice thereof in proper written form to the Secretary of the
Company. To be timely, a shareholder's notice must be delivered to or mailed and
received at the principal executive offices of the Company not less than 90 days
nor more than 120 days prior to the anniversary date of the immediately
preceding annual meeting of shareholders; provided, however, that in the event
that the annual meeting is called for a date that is not within 30 days before
or after such anniversary date, notice by the shareholder in order to be timely
must be received not later than the close of business on the 10th day following
the day on which such notice of the date of the annual meeting was mailed or, if
earlier, the day on which public announcement of the date of the annual meeting
was made. In no event shall the public announcement of an adjournment or
postponement of an annual meeting commence a new time period for the giving of a
shareholder's notice as described above. To be in proper written form, a
shareholder's notice to the Secretary shall set forth in writing as to each
matter the shareholder proposes to bring before the meeting (i) a brief
description of such matter and the reasons for conducting such business at the
annual meeting, (ii) the name and address, as they appear on the Company's
books, of the shareholder proposing such business, (iii) the number of shares of
stock of the Company which are beneficially owned by the shareholder, (iv) a
description of all arrangements or understandings between such shareholder and
any other person(s) (including their names) in connection with the proposal of
such business by such shareholder and any material interest of the shareholder
in such business and (v) a representation that such shareholder intends to
appear in person or by proxy at the annual meeting to bring such business before
the meeting. Notwithstanding anything in the By-laws to the contrary, no
business shall be conducted at an annual meeting except in accordance with the
procedures set forth in this Section 1(b).

                                      -4-
<PAGE>
 
The chairman of an annual meeting at which any business is proposed by a
shareholder shall have sole authority to determine, if the facts warrant, that
such business was not properly brought before the meeting in accordance with the
provisions of this Section 1(b), and, if he should so determine, he shall so
declare to the meeting and any such business not properly brought before the
meeting shall not be transacted. For purposes of this Section 1(b), "public
announcement" shall include disclosure in a press release issued to one or more
national financial or general news services or in a document publicly filed by
the Company with the Securities and Exchange Commission pursuant to Section 13,
14 or 15(d) of the Securities Exchange Act of 1934, as amended.

  SECTION 2.  Special meetings of the shareholders may be called by the
Chairman, by the Board of Directors, by a majority of the Directors individually
or by the holders of not less than one-fifth of the total outstanding shares of
capital stock of the Company.

  SECTION 3.  Written notice stating the place, day and hour of the meeting of
the shareholders and, in the case of a special meeting, the purpose or purposes
for which the meeting is called shall be delivered not less than ten nor more
than sixty days before the date of the meeting, or in the case of a merger,
consolidation, share exchange, dissolution or sale, lease or exchange of assets
not less than twenty nor more than sixty days before the date of the meeting,
either personally or by mail, by or at the direction of the Chairman, the
Secretary or the persons calling the meeting, to each shareholder of record
entitled to vote at such meeting.  If mailed, such notice shall be deemed to be
delivered when deposited in the United States mail addressed to the shareholder
at the shareholder's address as it appears upon the records of the Company, with
postage thereon prepaid.

  SECTION 4.  At all meetings of the shareholders, a majority of the outstanding
shares of stock, entitled to vote on a matter, represented in person or by
proxy, shall constitute a quorum for consideration of such matter, but the
shareholders represented at any meeting, though less than a quorum, may adjourn
the meeting to some other day or sine die.  If a quorum is present, the
affirmative vote of the majority of the shares of stock represented at the
meeting and entitled to vote on a matter shall be the act of the shareholders,
unless the vote of 

                                      -5-
<PAGE>
 
a greater number or voting by classes is required by law or the articles of 
incorporation.

  SECTION 5.  At every meeting of the shareholders, each outstanding share of
stock shall be entitled to one vote on each matter submitted for a vote.  In all
elections for Directors, every shareholder shall have the right to vote the
number of shares owned by such shareholder for as many persons as there are
Directors to be elected, or to cumulate such votes and give one candidate as
many votes as shall equal the number of Directors to be elected multiplied by
the number of such shares or to distribute such cumulative votes in any
proportion among any number of candidates.  A shareholder may vote either in
person or by proxy.  A shareholder may appoint a proxy to vote or otherwise act
for him or her by signing an appointment form and delivering it to the person so
appointed.

  SECTION 6.  Any meeting at which a quorum of shareholders is present, in
person or by proxy, may adjourn from time to time without notice, other than
announcement at such meeting, until its business is completed.  At the adjourned
meeting, the Company may transact any business which might have been transacted
at the original meeting.  If the adjournment is for more than thirty days, a
notice of the adjourned meeting shall be given to each shareholder of record
entitled to vote at the meeting.

  SECTION 7.  The Secretary of the Company shall make or cause to be made,
within twenty days after the record date for a meeting of shareholders of the
Company or ten days before such meeting, whichever is earlier, a complete list
of the shareholders entitled to vote at such meeting, arranged in alphabetical
order, with the address of and the number of shares held by each, which list,
for at least ten days prior to such meeting, shall be kept on file at the
registered office of the Company and shall be subject to inspection by any
shareholder, and to copying at such shareholder's expense, at any time during
usual business hours.  Such list shall also be produced and kept open at the
time and place of the meeting and shall be subject to the inspection of any
shareholder during the whole time of the meeting.

  SECTION 8.  The Chairman and the Secretary of the Company shall, when present,
act as chairman and secretary, respectively, of each meeting of the
shareholders.

                                      -6-
<PAGE>
 
  SECTION 9.  At any meeting of shareholders, the chairman of the meeting may,
or upon the request of any shareholder shall, appoint one or more persons as
inspectors for such meeting, unless an inspector or inspectors shall have been
previously appointed for such meeting by the Chairman.  Such inspectors shall
ascertain and report the number of shares of stock represented at the meeting,
based upon their determination of the validity and effect of proxies, count all
votes and report the results and do such other acts as are proper to conduct the
election and voting with impartiality and fairness to all the shareholders.

  SECTION 10.  Voting on any question or in any election may be viva voce unless
the presiding officer shall order or any shareholder shall demand that voting be
by ballot.

  Section 11.  Only persons who are nominated in accordance with the procedures
set forth in this Section 11 shall be eligible for election at a meeting of
shareholders as directors of the Company.  Nominations of persons for election
to the Board of Directors of the Company may be made at a meeting of
shareholders (a) by or at the direction of the Board of Directors or a committee
of the Board of Directors or (b) by any shareholder of the Company who is a
shareholder of record at the time of giving of notice provided for in this
Section, who shall be entitled to vote for the election of directors at the
meeting and who complies with the procedures set forth in this Section 11.  Any
nomination by a shareholder shall be made pursuant to timely notice in writing
to the Secretary of the Company.  To be timely, a shareholder's notice shall be
delivered to or mailed and received at the principal executive offices of the
Company not less than 90 days nor more than 120 days prior to the anniversary
date of the immediately preceding annual meeting of shareholders; provided,
however, that in the event that the annual meeting is called for a date that is
not within 30 days before or after such anniversary date, notice by the
shareholder in order to be timely must be received not later than the close of
business on the 10th day following the day on which such notice of the date of
the annual meeting was mailed or, if earlier, the day on which public
announcement of the date of the annual meeting was made.  In no event shall the
public announcement of an adjournment or postponement of an annual meeting
commence a new time period for the giving of a shareholder's notice as described
above.  Such shareholder's 

                                      -7-
<PAGE>
 
notice shall set forth (a) as to each person whom the shareholder proposes to
nominate for election or re-election as a director, all information relating to
such person that is required to be disclosed in solicitations of proxies for
election of directors, or is otherwise required, in each case pursuant to
Regulation 14A promulgated under the Securities Exchange Act of 1934, as amended
(including, without limitation, such person's written consent to being named in
the proxy statement as a nominee and to serving as a director if elected); and
(b) as to the shareholder giving the notice (i) the name and address, as they
appear on the Company's books, of such shareholder, (ii) the number of shares of
stock of the Company which are beneficially owned by such shareholder, (iii) a
description of all arrangements or understandings between such shareholder and
each proposed nominee and any other person(s) (including their names) pursuant
to which the nomination(s) are made by such shareholder, (iv) a representation
that such shareholder intends to appear in person or by proxy at the meeting to
nominate the persons named in such shareholder's notice and (v) any other
information relating to such shareholder that is or would be required to be
disclosed pursuant to Regulation 14A promulgated under the Securities Exchange
Act of 1934, as amended. At the request of the Board of Directors, any person
nominated by the Board of Directors for election as a director shall furnish to
the Secretary of the Company that information required to be set forth in a
shareholder's notice of nomination which pertains to the nominee. The chairman
of the meeting at which a shareholder nomination is presented shall have sole
authority to determine, if the facts warrant, that a nomination was not made in
accordance with the procedures prescribed by this Section 11, and if he should
so determine, he shall so declare to the meeting and the defective nomination
shall be disregarded. Notwithstanding the foregoing provisions of this Section
11, a shareholder shall also comply with all applicable requirements of the
Securities Exchange Act of 1934, as amended, and the rules and regulations
thereunder with respect to the matters set forth in this Section. For purposes
of this Section 11, "public announcement" shall include disclosure in a press
release issued to one or more national financial or general news services or in
a document publicly filed by the Company with the Securities and Exchange
Commission pursuant to Section 13, 14 or 15(d) of the Securities Exchange Act of
1934, as amended.

                                      -8-
<PAGE>
 
                                 ARTICLE III.

                              BOARD OF DIRECTORS.

  SECTION 1.  The business and affairs of the Company shall be managed by or
under the direction of the Board of Directors.  The number of Directors of the
Company shall be not less than eight nor more than thirteen.  The Directors
shall be elected at each annual meeting of the shareholders, but if for any
reason the election shall not be held at an annual meeting, it may be
subsequently held at any special meeting of the shareholders called for that
purpose after proper notice.  The Directors so elected shall hold office until
the next annual meeting and until their respective successors, willing to serve,
shall have been elected and qualified.  Directors need not be residents of the
State of Illinois or shareholders of the Company.  No person shall be eligible
for nomination or renomination as a Director by the management of the Company
who, prior to the date of election, shall have attained age seventy-two.  No
person who is an employe or a former employe of the Company or of a subsidiary
of the Company shall be eligible for nomination or renomination as a Director by
the management of the Company for a term commencing after such person ceases to
be such an employe; provided, however, that any Director of the Company who was
a Director of Commonwealth Edison Company, an Illinois corporation, in office on
June 15, 1989 who is or has been such an employe may be renominated as a
Director unless such person shall have attained age sixty-five on or before the
date of election of Directors.

  SECTION 2.  Any vacancy occurring in the Board of Directors, including a
vacancy created by an increase in the number of directors, may be filled by
election at an annual meeting or at a special meeting of shareholders called for
that purpose; provided, however, that any vacancy in the Board of Directors
arising between meetings of shareholders by reason of an increase in the number
of directors or otherwise may be filled by the vote of a majority of the
directors then in office, although less than a quorum.  Any directors so elected
shall serve until the next annual meeting of shareholders.

  SECTION 3.  A meeting of the Board of Directors shall be held immediately, or
as soon as practicable, after the annual election of Directors in each year,
provided a quorum for such meeting can be obtained.  Notice of every meeting of
the Board, 

                                      -9-
<PAGE>
 
stating the time and place at which such meeting will be held, shall be given to
each Director personally, by telephone or by other means of communication at
least one day, or by depositing the same in the mails properly addressed at
least two days before the day of such meeting. A meeting of the Board of
Directors may be called at any time by the Chairman or by any two Directors and
shall be held at such place as shall be specified in the notice for such
meeting.

  SECTION 4.  A majority of the number of Directors then in office, but not less
than six, shall constitute a quorum for the transaction of business at any
meeting of the Board, but a lesser number may adjourn the meeting from time to
time until a quorum is obtained, or may adjourn sine die.  The act of the
majority of the Directors present at a meeting at which a quorum is present
shall be the act of the Board of Directors.

  SECTION 5.  Each member of the Board not receiving a salary from the Company
or a subsidiary of the Company shall be paid such fees as the Board of Directors
may from time to time, by resolution adopted by the affirmative vote of a
majority of the Directors then in office, and irrespective of any personal
interest of any of its members, determine.  The Directors shall be paid their
reasonable expenses, if any, of attendance at each meeting of the Board of
Directors.  Members of any committee of the Board of Directors may be allowed
like fees and expenses for service on or attendance at meetings of such
committee.  No such payment shall preclude any Director from serving the Company
in any other capacity and receiving compensation therefor.

  SECTION 6.  A Director of the Company who is present at a meeting of the Board
of Directors at which action is taken on any corporate matter shall be
conclusively presumed to have assented to the action taken unless his or her
dissent shall be entered in the minutes of the meeting or unless he shall file
his or her written dissent to such action with the person acting as Secretary of
the meeting before the adjournment thereof or shall forward such dissent by
registered mail to the Secretary of the Company immediately after the
adjournment of the meeting.  Such right to dissent shall not apply to a director
who voted in favor of such action.

  SECTION 7.  At the first meeting of the Board of Directors following the
annual meeting of shareholders each year, the Board shall elect a Lead Director.
The Lead Director shall be 

                                      -10-
<PAGE>
 
elected from among the Outside Directors of the Company. For purposes hereof,
"Outside Directors" shall be those who are not and never have been employees of
the Company or any of its direct or indirect subsidiaries. The duties of the
Lead Director shall be to convene and chair meetings of the Outside Directors
and to assume other responsibilities which the Outside Directors might designate
from time to time. The Lead Director will consult with other Outside Directors
as to appropriate items for discussion at each such meeting.

                                  ARTICLE IV.

                     COMMITTEES OF THE BOARD OF DIRECTORS

  SECTION 1.  The Board of Directors may from time to time create committees,
standing or special, each committee to consist of two or more Directors of the
Company, and the Board shall appoint Directors to serve on such committees and
confer such powers upon such committees and revoke such powers and terminate the
existence of such committees, as the Board at its pleasure may determine,
subject to the limitations set forth in Section 8.40(c) of the Illinois Business
Corporation Act of 1983, as amended from time to time.

  SECTION 2.  Meetings of any committee of the Board may be called at any time
by the Chairman, by any two Directors or by the chairman of the committee the
meeting of which is being called and shall be held at such place as shall be
designated in the notice of such meeting.  Notice of each committee meeting
stating the time and place at which such meeting will be held shall be given to
each member of the committee personally, or by telecopy, or by depositing the
same in the mails properly addressed, at least one day before the day of such
meeting.  A majority of the members of a committee shall constitute a quorum
thereof but a lesser number may adjourn the meeting from time to time until a
quorum is obtained, or may adjourn sine die.  A majority vote of the members of
a committee present at a meeting at which a quorum is present shall be necessary
for committee action.

  SECTION 3.  The Board of Directors may from time to time designate from among
the Directors alternates to serve on one or more committees as occasion may
require.  Whenever a quorum cannot be secured for any meeting of any committee
from among the regular members thereof and designated alternates, the 

                                      -11-
<PAGE>
 
member or members of such committee present at such meeting and not disqualified
from voting thereat, whether or not he or they constitute a quorum, may
unanimously appoint another member of the Board of Directors to act at the
meeting in place of such absent or disqualified member.

  SECTION 4.  Every Director of the Company, or member of any committee
designated by the Board of Directors pursuant to authority conferred by these
By-Laws, shall, in the performance of his or her duties, be fully protected in
relying in good faith upon the records of the Company and upon such information,
opinions, reports or statements presented to the Company by any of the Company's
officers or employees, or committees of the Board of Directors, or by any other
person as to matters the Director or member reasonably believes are within such
other person's professional or expert competence and who has been selected with
reasonable care by or on behalf of the Company.

  SECTION 5.  Unless otherwise limited by the Board of Directors and subject to
the limitations set forth in the next sentence, each committee of the Board of
Directors consisting of two or more Directors may exercise the authority of the
Board.  Notwithstanding any other provision of the By-Laws, no committee of the
Board of Directors shall:  (1) authorize distributions; (2) approve or recommend
to shareholders any act required by law to be approved by shareholders; (3) fill
vacancies on the Board of Directors or on any of its committees; (4) elect or
remove officers or fix the compensation of any member of the committee; (5)
adopt, amend or repeal the By-Laws; (6) approve a plan of merger not requiring
shareholder approval; (7) authorize or approve reacquisition of stock, except
according to a general formula or method prescribed by the Board of Directors;
(8) authorize or approve the issuance or sale, or contract for sale, of stock or
determine the designation and relative rights, preferences, and limitations of a
series of stock, except that a committee may fix the specific terms of the
issuance or sale or contract for sale or the number of shares of stock to be
allocated to particular employees under an employee benefit plan; or (9) amend,
alter, repeal, or take action inconsistent with any resolution or action of the
Board of Directors when the resolution or action of the Board of Directors
provides by its terms that it shall not be amended, altered or repealed by
action of a committee.

                                      -12-
<PAGE>
 
                                 ARTICLE V.

                                 OFFICERS.

  SECTION 1.  There shall be elected by the Board of Directors, at its first
meeting after the annual election of Directors in each year if practicable, the
following principal officers of the Company, namely: a Chairman, a President,
such number of Executive Vice Presidents, Senior Vice Presidents and Vice
Presidents as the Board at the time may decide upon, a Secretary, a Treasurer
and a Comptroller; and the Board may also provide for a Vice Chairman and such
other officers, and prescribe for each of them such duties, as in its judgment
may from time to time be desirable to conduct the affairs of the Company.  No
officer shall be elected for a term extending beyond the first day of the month
following the month in which such officer attains the age of 65 years, on which
date such officer shall be retired.  The Chairman shall be a Director of the
Company; any other officer above named may, but need not, be a Director of the
Company.  Any two or more offices may be held by the same person.  All officers
shall hold their respective offices until the first meeting of the Board of
Directors after the next succeeding annual election of Directors and until their
successors, willing to serve, shall have been elected, but any officer may be
removed from office by the Board of Directors whenever in its judgment the best
interests of the Company will be served thereby.  Such removal, however, shall
be without prejudice to the contract rights, if any, of the person so removed.
Election of an officer shall not of itself create contract rights.

  SECTION 2.  The Chairman shall be the chief executive officer of the Company
and shall have general authority over all the affairs of the Company, including
the power to appoint and discharge any and all officers, agents and employes of
the Company not elected or appointed directly by the Board of Directors.  The
Chairman shall, when present, preside at all meetings of the shareholders and of
the Board of Directors.  The Chairman shall have authority to call special
meetings of the shareholders and meetings of the Board of Directors, and of any
committee of the Board of Directors and, when neither the Board of Directors nor
the Executive Committee is in session, to suspend the authority of any other
officer or officers of the Company, subject, however, to the pleasure of the
Board of 

                                      -13-
<PAGE>
 
Directors or of the Executive Committee at its next meeting. The Chairman, or
such other officer as the Chairman may direct, shall be responsible for all
internal audit functions, and the internal audit personnel shall report directly
to the Chairman or to such other officer.

  SECTION 3.  If, at any time, it is brought to the attention of any Director
that the Chairman has or may become absent or disabled and may thereby be unable
to perform the duties of Chairman for some period of time, the Lead Director
shall, as promptly as practicable upon his own initiative, or after notice from
another Director, convene a meeting (in person or by telephone conference call)
of the Outside Directors (who for purposes hereof shall consist of all Directors
who are not and have never been employees of the Company or any of its direct or
indirect subsidiaries) who shall decide whether the Chairman has become absent
or disabled.  Upon such determination, the Outside Directors shall designate an
Acting Chairman, who may be the Lead Director or any other Director of the
Company, and who shall exercise the power and duties of the Chairman until the
Outside Directors shall have determined that the Chairman can resume his duties
as Chairman or until a new Chairman has been elected by the Board of Directors.
The Acting Chairman, however, shall have no authority to make changes in the
persons holding any office at the executive payroll level of the Company or to
make changes in any such person's duties or responsibilities, or compensation or
benefits, without prior approval of the Board of Directors.  For purposes of
this Section, any action of the Outside Directors shall be by majority vote of
those present at a meeting of such Directors, provided that a majority of such
Directors shall constitute a quorum for such a meeting.

  SECTION 4.  Except insofar as the Board of Directors, the Executive Committee
or the Chairman shall have devolved responsibilities on the other principal
officers, the President shall be responsible for the general management and
direction of the affairs of the Company, subject to the control of the Board of
Directors, the Executive Committee and the Chairman.  The President shall have
such other powers and duties as usually devolve upon the President of a
corporation and such further powers and duties as may be prescribed by the Board
of Directors, the Executive Committee or the chairman.  The President shall
report to the Chairman.

                                      -14-
<PAGE>
 
  SECTION 5.  The Executive Vice Presidents, the Senior Vice Presidents and the
Vice Presidents shall have such powers and duties as may be prescribed for them,
respectively, by the Board of Directors, the Executive committee or the
Chairman.  Each of such officers shall report to the Chairman or such other
officer as the Chairman shall direct.

  SECTION 6.  The Secretary shall attend all meetings of the shareholders, of
the Board of Directors and of each committee of the Board of Directors, shall
keep a true and faithful record thereof in proper books and shall have the
custody and care of the corporate seal, records, minute books and stock books of
the Company and of such other books and papers as in the practical business
operations of the Company shall naturally belong in the office or custody of the
Secretary or as shall be placed in the Secretary's custody by order of the Board
of Directors or the Executive Committee.  The Secretary shall keep or cause to
be kept a suitable record of the addresses of shareholders and shall, except as
may be otherwise required by statute or the by-laws, sign and issue all notices
required for meetings of shareholders, of the Board of Directors and of the
committees of the Board of Directors.  Whenever requested by the requisite
number of shareholders or Directors, the Secretary shall give notice, in the
name of the shareholder or shareholders or Director or Directors making the
request, of a meeting of the shareholders or of the Board of Directors or of a
committee of the Board of Directors, as the case may be.  The Secretary shall
sign all papers to which the Secretary's signature may be necessary or
appropriate, shall affix and attest the seal of the Company to all instruments
requiring the seal, shall have the authority to certify the by-laws, resolutions
of the shareholders and Board of Directors and committees of the Board of
Directors and other documents of the Company as true and correct copies thereof
and shall have such other powers and duties as are commonly incidental to the
office of Secretary and as may be prescribed by the Board of Directors, the
Executive Committee or the Chairman.  The Secretary shall report to the Chairman
or such other officer as the Chairman shall direct.

  SECTION 7.  The Treasurer shall have charge of and be responsible for the
collection, receipt, custody and disbursement of the funds of the Company.  The
Treasurer shall deposit the Company's funds in its name in such banks, trust
companies or safe deposit vaults as the Board of Directors may direct.  Such
funds shall be subject to withdrawal only upon 

                                      -15-
<PAGE>
 
checks or drafts signed or authenticated in such manner as may be designated
from time to time by resolution of the Board of Directors or of the Executive
Committee. The Treasurer shall have the custody of such books and papers as in
the practical business operations of the Company shall naturally belong in the
office or custody of the Treasurer or as shall be placed in the Treasurer's
custody by order of the Board of Directors or the Executive Committee. The
Treasurer shall have such other powers and duties as are commonly incidental to
the office of Treasurer or as may be prescribed for the Treasurer by the Board
of Directors, the Executive Committee or the Chairman. Securities owned by the
Company shall be in the custody of the Treasurer or of such other officers,
agents or depositaries as may be designated by the Board of Directors or the
Executive Committee. The Treasurer may be required to give bond to the Company
for the faithful discharge of the duties of the Treasurer in such form and in
such amount and with such surety as shall be determined by the Board of
Directors. The Treasurer shall report to the Chairman or such other officer as
the Chairman shall direct.

  SECTION 8.  The Comptroller shall be responsible for the executive direction
of the accounting organization and shall have functional supervision over the
records of all other departments pertaining to revenues, expenses, money,
securities, properties, materials and supplies.  The Comptroller shall prescribe
the form of all vouchers, accounts and accounting procedures, and reports
required by the various departments.  The Comptroller shall be responsible for
the preparation and interpretation of all accounting reports and financial
statements as required and for the proper review and approval of all bills
received for payment.  No bill or voucher shall be so approved unless the
charges covered by the bill or voucher shall have been previously approved
through job order, requisition or otherwise by the head of the department in
which it originated, or unless the Comptroller shall otherwise be satisfied of
its propriety and correctness.  The Comptroller shall have such other powers and
duties as are commonly incidental to the office of Comptroller or as may be
prescribed for the Comptroller by the Board of Directors, the Executive
Committee or the Chairman.  The Comptroller may be required to give bond to the
Company for the faithful discharge of the duties of the Comptroller in such form
and in such amount and with such surety as shall be determined by the Board of
Directors.  The Comptroller shall 

                                      -16-
<PAGE>
 
report to the Chairman or such other officer as the Chairman shall direct.

  SECTION 9.  Assistant Secretaries, Assistant Treasurers and Assistant
Comptrollers, when elected or appointed, shall respectively assist the
Secretary, the Treasurer and the Comptroller in the performance of the
respective duties assigned to such principal officers, and in assisting such
principal officer, each of such assistant officers shall for such purpose have
the powers of such principal officer.  In case of the absence, disability,
death, resignation or removal from office of any principal officer, such
principal officer's duties shall, except as otherwise ordered by the Board of
Directors or the Executive Committee, temporarily devolve upon such assistant
officer as shall be designated by the Chairman.

  SECTION 10.  At least once each year, the Chairman shall report (which may be
oral) to the Outside Directors (who for purposes hereof shall consist of all
Directors who are not and never have been employees of the Company or any of its
direct or indirect subsidiaries) on the status of a plan for succession to the
office of Chairman.

                                  ARTICLE VI.

                               INDEMNIFICATION.

  SECTION 1.  (a) A Director of the Company shall not be personally liable to
the Company or its shareholders for monetary damages for breach of fiduciary
duty as a Director, except for liability (i) for any breach of the Director's
duty of loyalty to the Company or its shareholders, (ii) for acts or omissions
not in good faith or that involve intentional misconduct or a knowing violation
of law, (iii) under Section 8.65 of the Illinois Business Corporation Act of
1983, as amended, or (iv) for any transaction from which the Director derived an
improper personal benefit.  If the Illinois Business Corporation Act of 1983 is
amended to authorize corporate action further eliminating or limiting the
personal liability of Directors, then the liability of a Director of the Company
shall be eliminated or limited to the full extent permitted by the Illinois
Business Corporation Act of 1983, as so amended.  Any repeal or modification of
this Section 1(a) by the shareholders of the Company shall not adversely affect
any right or protection of a 

                                      -17-
<PAGE>
 
Director of the Company existing at the time of such repeal or modification.

  (b) Each person who is or was or had agreed to become a Director or officer of
the Company, and each person who is or was serving or who had agreed to serve at
the request of the Board of Directors or an officer of the Company as an employe
or agent of the Company or as a director, officer, employe, or agent, trustee or
fiduciary of another corporation, partnership, joint venture, trust or other
enterprise (including the heirs, executors, administrators or estate of such
person), shall be indemnified by the Company to the full extent permitted by the
Illinois Business Corporation Act of 1983 or any other applicable laws as
presently or hereafter in effect.  Without limiting the generality of the
foregoing, the Company may enter into one or more agreements with any person
which provide for indemnification greater or different than that provided in
this Section 1(b).  Any repeal or modification of this Section 1(b) shall not
adversely affect any right or protection existing hereunder immediately prior to
such repeal or modification.

  SECTION 2.  The provisions of this Article shall be deemed to be a contract
between the Company and each Director or officer who serves in any such capacity
at any time while this Article is in effect, and any repeal or modification of
this Article shall not affect any rights or obligations hereunder with respect
to any state of facts then or theretofore existing or any action, suit or
proceeding theretofore or thereafter brought or threatened based in whole or in
part upon any such state of facts.

  SECTION 3.  The indemnification provided or permitted by this Article shall
not be deemed exclusive of any other rights to which those indemnified may be
entitled by law or otherwise, and shall continue as to a person who has ceased
to be a Director, officer, employee or agent and shall inure to the benefit of
the heirs, executors and administrators of such person.

  SECTION 4.  The Company may purchase and maintain insurance on behalf of any
person who is or was a Director, officer, employee or agent of the Company, or
who is or was serving at the request of the Company as a director, officer,
employee or agent of another corporation or of a partnership, joint venture,
trust or other enterprise, against any liability asserted 

                                     -18-
<PAGE>
 
against such person and incurred by such person in any such capacity, or arising
out of his or her status as such, whether or not the Company would have the
power to indemnify such person against such liability under the laws of the
State of Illinois.

                                 ARTICLE VII.

                                 MISCELLANEOUS.

  SECTION 1.  No bills shall be paid by the Treasurer unless reviewed and
approved by the Comptroller or by some other person or committee expressly
authorized by the Board of Directors, the Executive Committee, the Chairman or
the Comptroller to review and approve bills for payment.

  SECTION 2.  All checks, drafts or other orders for payment of money issued in
the name of the Company shall be signed by such officers, employees or agents of
the Company as shall from time to time be designated by the Board of Directors,
the Chairman, the chief financial officer of the Company or the Treasurer.

  SECTION 3.  Any and all shares of stock of any corporation owned by the
Company and any and all voting trust certificates owned by the Company calling
for or representing shares of stock of any corporation may be voted at any
meeting of the shareholders of such corporation or at any meeting of the holders
of such certificates, as the case may be, by any one of the principal officers
of the Company upon any question which may be presented at such meeting, and any
such officer may, on behalf of the Company, waive any notice required to be
given of the calling of such meeting and consent to the holding of any such
meeting without notice. Any such principal officer other than the Secretary,
acting together with the Secretary or an Assistant Secretary, shall have
authority to give to any person a written proxy, in the name of the Company and
under its corporate seal, to vote any or all shares of stock or any or all
voting trust certificates owned by the Company upon any question that may be
presented at any such meeting of shareholders or certificate holders, with full
power to waive any notice of the calling of such meeting and consent to the
holding of such meeting without notice.

                                      -19-
<PAGE>
 
  SECTION 4.  The fiscal year of the Company shall begin on the first day of
January and end on the last day of December in each year.

                                 ARTICLE VIII.

                  ALTERATION, AMENDMENT OF REPEAL OF BY-LAWS.

  These by-laws may be altered, amended or repealed by the shareholders or the
Board of Directors.

                                      -20-