POWER OF ATTORNEY

	The undersigned hereby constitutes and appoints
Louis J. Briskman and Angeline C. Straka, and each of them
singly, the undersigned's true and lawful attorney-in-fact to
execute and file for and on behalf of the undersigned (i) any
reports on Forms 3, 4  and 5 (including any amendments
thereto and any successors to such Forms) with respect to
ownership of securities of CBS Corporation, formerly known as
Viacom Inc. (the "Company"), that the undersigned may be required
to file with the U.S. Securities and Exchange Commission
in accordance with Section 16(a) of the Securities Exchange Act
of 1934 and the rules thereunder and (ii) any other documents
necessary or appropriate to obtain codes and passwords enabling
the undersigned to file such reports electronically.

	The undersigned acknowledges that the foregoing
attorney-in-fact, in serving in such capacity at the request
of the undersigned, is not assuming, nor is the Company
assuming, any of the undersigned's responsibilities to
comply with Section 16 of the Securities Exchange Act of 1934.

	This Power of Attorney shall remain in full force
and effect until the undersigned is no longer required to file
Forms 3, 4 and 5 with respect to the undersigned's holdings and
transactions in securities issued by the Company, unless earlier
revoked by the undersigned in a signed writing delivered to
the foregoing attorney-in-fact.   This Power of Attorney revokes
and replaces any prior Power of Attorney executed by the
undersigned with respect to the ownership of securities of the Company.

	IN WITNESS WHEREOF, the undersigned has caused this Power of
Attorney to be executed as of this 19th day of  December, 2005.


		Signature:  /s/ Anthony G. Ambrosio
		Print: Anthony G. Ambrosio