EXHIBIT 24
POWER OF ATTORNEY
We, the undersigned, hereby constitute Charles W. Cramb and Richard K.
Willard, or either of them, our true and lawful attorneys with full power to
sign for us in our name and in the capacity indicated below, the Annual Report
on Form 10-K pursuant to Section 13 of the Securities Exchange Act of 1934,
filed for the Company with the Securities and Exchange Commission for the year
ended December 31, 2001, and any and all amendments and supplements thereto,
hereby ratifying and confirming our signatures as they may be signed by our said
attorneys, or either of them, to said Report and to any and all amendments and
supplements to said Report.
WITNESS Our Hand and Seal on the Date set forth below.
<Table>
<Caption>
SIGNATURES TITLE DATE
---------- ----- ----
/s/ JAMES M. KILTS Chairman of the Board of of March 14, 2002
- --------------------------------------------------- Directors, Chief Executive
James M. Kilts Officer and Director
/s/ EDWARD F. DEGRAAN President, Chief Operating March 14, 2002
- --------------------------------------------------- Officer and Director
Edward F. DeGraan
/s/ CHARLES W. CRAMB Senior Vice President and Chief March 14, 2002
- --------------------------------------------------- Financial Officer
Charles W. Cramb
/s/ CLAUDIO E. RUBEN Vice President, Controller and March 14, 2002
- --------------------------------------------------- Principal Accounting Officer
Claudio E. Ruben
/s/ WARREN E. BUFFETT Director March 14, 2002
- ---------------------------------------------------
Warren E. Buffett
/s/ WILBUR H. GANTZ Director March 14, 2002
- ---------------------------------------------------
Wilbur H. Gantz
/s/ MICHAEL B. GIFFORD Director March 14, 2002
- ---------------------------------------------------
Michael B. Gifford
/s/ CAROL R. GOLDBERG Director March 14, 2002
- ---------------------------------------------------
Carol R. Goldberg
/s/ DENNIS F. HIGHTOWER Director March 14, 2002
- ---------------------------------------------------
Dennis F. Hightower
/s/ HERBERT H. JACOBI Director March 14, 2002
- ---------------------------------------------------
Herbert H. Jacobi
/s/ HENRY R. KRAVIS Director March 14, 2002
- ---------------------------------------------------
Henry R. Kravis
/s/ JORGE PAULO LEMANN Director March 14, 2002
- ---------------------------------------------------
Jorge Paulo Lemann
/s/ RICHARD R. PIVIROTTO Director March 14, 2002
- ---------------------------------------------------
Richard R. Pivirotto
/s/ MARJORIE M. YANG Director March 14, 2002
- ---------------------------------------------------
Marjorie M. Yang
</Table>