Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2011

Financial Instruments [Abstract]

Marketable Securities including Strategic Investments

As of December 31, 2011 (In millions):	Fair Value		Gross Unrealized Gains		Gross Unrealized Losses			Amortized Cost
Available-for-sale
Corporate debt securities:
Current	$	155.0	$	0.2	$	(0.1	)	$	154.9
Non-current		447.6		1.2		(1.5	)		447.9
Government securities:
Current		1,021.0		0.4		—			1,020.6
Non-current		695.5		0.9		(0.2	)		694.8
Mortgage and other asset backed securities:
Current		0.1		—		—			0.1
Non-current		273.7		0.5		(1.3	)		274.5
Total available-for-sale securities	$	2,592.9	$	3.2	$	(3.1	)	$	2,592.8
Other Investments
Strategic investments, non-current	$	0.1	$	—	$	(0.1	)	$	0.2

As of December 31, 2010 (In millions):	Fair Value		Gross Unrealized Gains		Gross Unrealized Losses			Amortized Cost
Available-for-sale
Corporate debt securities:
Current	$	93.2	$	0.1	$	—		$	93.1
Non-current		219.8		2.1		(0.5	)		218.2
Government securities:
Current		352.8		0.2		—			352.6
Non-current		432.5		0.6		(0.6	)		432.5
Mortgage and other asset backed securities:
Current		2.1		—		—			2.1
Non-current		90.8		0.5		(0.2	)		90.5
Total available-for-sale securities	$	1,191.2	$	3.5	$	(1.3	)	$	1,189.0
Other Investments
Strategic investments, non-current	$	44.8	$	17.5	$	—		$	27.3

Summary of financial assets with original maturities of less than 90 days included within cash and cash equivalents

	As of December 31,
(In millions)	2011		2010
Commercial paper	$	—	$	4.0
Repurchase agreements		8.8		26.0
Short-term debt securities		391.0		621.8
Total	$	399.8	$	651.8

Summary of Contractual Maturities: Available-for-Sale Securities

	As of December 31, 2011				As of December 31, 2010
(In millions)	Estimated Fair  Value		Amortized Cost		Estimated Fair  Value		Amortized Cost
Due in one year or less	$	1,176.1	$	1,175.6	$	448.1	$	447.8
Due after one year through five years		1,251.6		1,251.4		664.1		662.4
Due after five years		165.2		165.8		79.0		78.8
Total available-for-sale securities	$	2,592.9	$	2,592.8	$	1,191.2	$	1,189.0

Proceeds from Marketable Securities, excluding Strategic Investments

	For the Years Ended December 31,
(In millions)	2011		2010		2009
Proceeds from maturities and sales	$	2,276.7	$	2,668.7	$	3,319.0
Realized gains	$	3.9	$	18.8	$	19.8
Realized losses	$	2.3	$	2.5	$	4.0