Share-Based Payments (Tables)

6 Months Ended

Jun. 30, 2011

Share-based Payments [Abstract]

Schedule of stock option and restricted stock unit grants

	For the Six Months
	Ended June 30,
	2011		2010
Stock options		—		124,000
Market stock units(a)		373,000		334,000
Cash settled performance shares(b)		483,000		373,000
Time-vested restricted stock units(c)		1,303,000		1,700,000
Performance-vested restricted stock units(d)		1,000		4,000

(a)	Market stock units (MSUs) granted for the six months ended June 30, 2010, represents the target number of shares eligible to be earned at the time of grant.
	MSUs granted for the six months ended June 30, 2011, includes approximately 18,000 additional MSUs issued in 2011 based upon the attainment of performance criteria set for 2010 in relation to shares granted in 2010. The remainder of the MSUs granted in 2011 represent the target number of shares eligible to be earned at the time of grant. These grants were made in conjunction with the hiring of employees and our annual awards made in February.
(b)	Cash settled performance shares (CSPSs) granted for the six months ended June 30, 2010, represents the target number of shares eligible to be earned at the time of grant.
	CSPSs granted for the six months ended June 30, 2011, includes approximately 95,000 additional CSPSs issued in 2011 based upon the attainment of performance criteria set for 2010 in relation to shares granted in 2010. The remainder of the CSPSs granted in 2011 represent the target number of shares eligible to be earned at the time of grant. These grants were made in conjunction with the hiring of employees and our annual awards made in February.
(c)	Time-vested restricted stock units (RSUs) granted for the six months ended June 30, 2011, includes approximately 1.2 million RSUs granted in connection with our annual awards made in February 2011, and 135,000 RSUs granted in conjunction with new hires and grants made to our Board of Directors.
(d)	Performance-vested restricted stock units (PVRSUs) granted for the six months ended June 30, 2010, represents the target number of shares eligible to be earned at the time of grant; approximately 1,000 additional PVRSUs were issued in 2011 based upon the attainment of performance criteria set for 2010 in relation to shares granted in 2010.

Share-based compensation expense included in consolidated statements of income

	For the Three Months						For the Six Months
	Ended June 30,						Ended June 30,
(In millions)	2011			2010			2011			2010
Research and development	$	13.9		$	15.4		$	32.2		$	32.1
Selling, general and administrative		22.2			34.0			42.8			70.2
Restructuring charges		—			—			(0.6	)		—
Subtotal		36.1			49.4			74.4			102.3
Capitalized share-based compensation costs		(1.0	)		(0.7	)		(2.0	)		(1.6	)
Share-based compensation expense included in total cost and expenses		35.1			48.7			72.4			100.7
Income tax effect		(10.9	)		(15.7	)		(23.0	)		(32.4	)
Share-based compensation expense included in net income attributable to Biogen Idec Inc	$	24.2		$	33.0		$	49.4		$	68.3

Summary of share-based compensation expense associated with different programs

	For the Three Months						For the Six Months
	Ended June 30,						Ended June 30,
(In millions)	2011			2010			2011			2010
Stock options	$	1.6		$	9.3		$	2.7		$	20.1
Market stock units		4.3			1.9			7.7			5.5
Time-vested restricted stock units		19.1			32.3			46.2			65.8
Performance-vested restricted stock units settled in shares		0.3			1.3			0.7			3.7
Cash settled performance shares		10.7			4.2			15.5			5.2
Employee stock purchase plan		0.1			0.4			1.6			2.0
Subtotal		36.1			49.4			74.4			102.3
Capitalized share-based compensation costs		(1.0	)		(0.7	)		(2.0	)		(1.6	)
Share-based compensation expense included in total cost and expenses	$	35.1		$	48.7		$	72.4		$	100.7