Share-Based Payments (Tables)

9 Months Ended

Sep. 30, 2013

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)	2013			2012			2013			2012
Research and development	$	20.7		$	18.0		$	69.6		$	55.8
Selling, general and administrative	39.9			27.7			119.5			81.5
Subtotal	60.6			45.7			189.1			137.3
Capitalized share-based compensation costs	(2.4		)	(1.5		)	(7.4		)	(4.0		)
Share-based compensation expense included in total cost and expenses	58.2			44.2			181.7			133.3
Income tax effect	(17.4		)	(13.0		)	(54.3		)	(40.1		)
Share-based compensation expense included in net income attributable to Biogen Idec Inc.	$	40.8		$	31.2		$	127.4		$	93.2

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)	2013			2012			2013			2012
Stock options	$	0.1		$	0.7		$	0.5		$	1.6
Market stock units	12.2			5.6			27.2			17.2
Time-vested restricted stock units	25.3			21.4			77.2			69.5
Performance-vested restricted stock units settled in shares	—			—			—			0.1
Cash settled performance shares	20.6			16.4			76.8			45.1
Employee stock purchase plan	2.4			1.6			7.4			3.8
Subtotal	60.6			45.7			189.1			137.3
Capitalized share-based compensation costs	(2.4		)	(1.5		)	(7.4		)	(4.0		)
Share-based compensation expense included in total cost and expenses	$	58.2		$	44.2		$	181.7		$	133.3

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

	For the Nine Months Ended September 30,
	2013	2012
Market stock units	268,000	312,000
Cash settled performance shares	273,000	327,000
Time-vested restricted stock units	708,000	902,000