LIMITED POWER OF ATTORNEY FOR
SECTION 16 REPORTING OBLIGATIONS


	Know all by these presents, that the undersigned hereby makes,
constitutes and appoints Susan H. Alexander, Aras Lapinskas, Robert A.
Licht, Robin A. Walker and Marcia J. Gookin as the undersigned's true and
lawful attorney-in-fact, with full power and authority as hereinafter
described on behalf of and in the name, place and stead of the undersigned to:

(1)	prepare, execute in the undersigned?s name and on the undersigned?s
 behalf, and submit to the U.S. Securities and Exchange Commission
(the ?SEC?) a Form ID, including amendments thereto, and any other documents
necessary or appropriate to obtain codes and passwords enabling the
undersigned to make electronic filings with the SEC of reports required
by Section 16(a) of the Securities Exchange Act of 1934 or any rule or
regulation of the SEC;

(2)	prepare, execute, acknowledge, deliver and file Forms 3, 4,
and 5 (including any amendments thereto) with respect to the securities
of Biogen Idec Inc., a Delaware corporation (the "Company"), with the
United States Securities and Exchange Commission, any national securities
exchanges and the Company, as considered necessary or advisable under
Section 16(a) of the Securities Exchange Act of 1934 and the rules and
regulations promulgated thereunder, as amended from time to time (the
"Exchange Act");

(3)	seek or obtain, as the undersigned's representative and on the
undersigned's behalf, information on transactions in the Company's
securities from any third party, including brokers, employee benefit
plan administrators and trustees, and the undersigned hereby authorizes
any such person to release any such information to the undersigned and
approves and ratifies any such release of information; and

(4)	perform any and all other acts which in the discretion of such
attorney-in-fact are necessary or desirable for and on behalf of the
undersigned in connection with the foregoing.

The undersigned acknowledges that:

(1)	this Limited Power of Attorney authorizes, but does not require,
such attorney-in-fact to act in their discretion on information provided
to such attorney-in-fact without independent verification of such
information;

(2)	any documents prepared and/or executed by such attorney-in-fact
on behalf of the undersigned pursuant to this Limited Power of Attorney
will be in such form and will contain such information and disclosure
as such attorney-in-fact, in his or her discretion, deems necessary or
desirable;

(3)	neither the Company nor such attorney-in-fact assumes (i) any
liability for the undersigned's responsibility to comply with the
requirement of the Exchange Act, (ii) any liability of the undersigned
for any failure to comply with such requirements, or (iii) any obligation
or liability of the undersigned for profit disgorgement under Section 16(b)
of the Exchange Act; and

(4)	this Limited Power of Attorney does not relieve the undersigned
from responsibility for compliance with the undersigned's obligations
under the Exchange Act, including without limitation the reporting
requirements under Section 16 of the Exchange Act.

	The undersigned hereby gives and grants the foregoing
attorney-in-fact full power and authority to do and perform all
and every act and thing whatsoever requisite, necessary or appropriate
to be done in and about the foregoing matters as fully to all intents
and purposes as the undersigned might or could do if present, hereby
ratifying all that such attorney-in-fact of, for and on behalf of
the undersigned, shall lawfully do or cause to be done by virtue of
this Limited Power of Attorney.

	This Limited Power of Attorney shall remain in full force
and effect until revoked by the undersigned in a signed writing
delivered to such attorney-in-fact.

	IN WITNESS WHEREOF, the undersigned has caused this
Limited Power of Attorney to be executed as of this 11th day of January, 2011.

                                        _/s/ Nancy L. Leaming__
					Signature

					Name:  Nancy L. Leaming