Share-Based Payments (Tables)

9 Months Ended

Sep. 30, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-based compensation expense included in consolidated statements of income

	For the Three Months Ended September 30,						For the Nine Months Ended September 30,
(In millions)	2012			2011			2012			2011
Research and development	$	18.0		$	14.2		$	55.8		$	46.4
Selling, general and administrative	27.7			22.4			81.5			65.2
Restructuring charges	—			—			—			(0.6		)
Subtotal	45.7			36.6			137.3			111.0
Capitalized share-based compensation costs	(1.5		)	(1.3		)	(4.0		)	(3.3		)
Share-based compensation expense included in total cost and expenses	44.2			35.3			133.3			107.7
Income tax effect	(13.0		)	(10.0		)	(40.1		)	(33.0		)
Share-based compensation expense included in net income attributable to Biogen Idec Inc.	$	31.2		$	25.3		$	93.2		$	74.7

Summary of share-based compensation expense associated with each of our share-based compensating programs

	For the Three Months Ended September 30,						For the Nine Months Ended September 30,
(In millions)	2012			2011			2012			2011
Stock options	$	0.7		$	1.8		$	1.6		$	4.5
Market stock units	5.6			3.5			17.2			11.2
Time-vested restricted stock units	21.4			22.0			69.5			68.2
Performance-vested restricted stock units settled in shares	—			0.2			0.1			0.9
Cash settled performance shares	16.4			6.2			45.1			21.7
Employee stock purchase plan	1.6			2.9			3.8			4.5
Subtotal	45.7			36.6			137.3			111.0
Capitalized share-based compensation costs	(1.5		)	(1.3		)	(4.0		)	(3.3		)
Share-based compensation expense included in total cost and expenses	$	44.2		$	35.3		$	133.3		$	107.7

Summary of equity grants to employees, officers and directors under our current stock plans

	For the Nine Months Ended September 30,
	2012	2011
Market stock units(a)	312,000	393,000
Cash settled performance shares(b)	327,000	490,000
Time-vested restricted stock units(c)	902,000	1,352,000
Performance-vested restricted stock units(d)	—	1,000

(a) Market stock units (MSUs) granted during the nine months ended September 30, 2012 include approximately 39,000 and 41,000 MSUs issued in 2012 based upon the attainment of performance criteria set for 2011 and 2010, respectively, in relation to shares granted in those years. The remainder of MSUs granted during the nine months ended September 30, 2012 include awards granted in conjunction with our annual awards made in February 2012 and MSUs granted in conjunction with the hiring of employees. These grants reflect the target number of shares eligible to be earned at the time of grant.

MSUs granted during the nine months ended September 30, 2011, include approximately 26,000 MSUs issued in 2011 based upon the attainment of performance criteria set for 2010 in relation to shares granted in 2010. The remainder of MSUs granted during the nine months ended September 30, 2011 include awards granted in conjunction with our annual awards made in February 2011 and MSUs granted in conjunction with the hiring of employees. These grants reflect the target number of shares eligible to be earned at the time of grant.

(b) Cash settled performance shares (CSPSs) granted during the nine months ended September 30, 2012 include approximately 68,000 CSPSs issued in 2012 based upon the attainment of performance criteria set for 2011 in relation to shares granted in 2011. The remainder of CSPSs granted during the nine months ended September 30, 2012 include awards granted in conjunction with our annual awards made in February 2012 and CSPSs granted in conjunction with the hiring of employees. These grants reflect the target number of shares eligible to be earned at the time of grant.

CSPSs granted during the nine months ended September 30, 2011, include approximately 95,000 CSPSs issued in 2011 based upon the attainment of performance criteria set for 2010 in relation to shares granted in 2010. The remainder of CSPSs granted during the nine months ended September 30, 2011 include awards granted in conjunction with our annual awards made in February 2011 and CSPSs granted in conjunction with the hiring of employees. These grants reflect the target number of shares eligible to be earned at the time of grant.

(c) Time-vested restricted stock units (RSUs) granted during the nine months ended September 30, 2012 primarily represent RSUs granted in conjunction with our annual awards made in February 2012 and awards made in conjunction with the hiring of new employees. RSUs granted during the nine months ended September 30, 2012 also include approximately 24,000 RSUs granted to our Board of Directors.

RSUs granted during the nine months ended September 30, 2011 primarily represent RSUs granted in conjunction with our annual awards made in February 2011 and awards made in conjunction with the hiring of new employees. RSUs granted during the nine months ended September 30, 2011 also include approximately 35,000 RSUs granted to our Board of Directors.

(d) Performance-vested restricted stock units (PVRSUs) granted during the nine months ended September 30, 2011 represent shares earned for performance criteria set for 2010 in relation to shares granted in 2010. No PVRSUs were granted during the nine months ended September 30, 2012.