Financial Instruments

Marketable Securities

The following tables summarize our marketable debt and equity securities:



As of December 31, 2012 (In millions)	Fair Value		Gross Unrealized Gains		Gross Unrealized Losses			Amortized Cost
Available-for-sale:
Corporate debt securities
Current	$	346.9	$	0.3	$	—		$	346.6
Non-current	654.1		2.8		(0.6		)	651.9
Government securities
Current	783.4		0.3		—			783.1
Non-current	874.4		0.8		—			873.6
Mortgage and other asset backed securities
Current	4.8		—		—			4.8
Non-current	508.1		1.4		(1.3		)	508.0
Total marketable debt securities	$	3,171.7	$	5.6	$	(1.9	)	$	3,168.0
Marketable equity securities, non-current	$	9.0	$	3.0	$	—		$	6.0



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 marketable debt securities	$	2,592.9	$	3.2	$	(3.1	)	$	2,592.8
Marketable equity securities, non-current	$	0.1	$	—	$	(0.1	)	$	0.2

In the table above, as of December 31, 2011, government securities included $214.0 million of Federal Deposit Insurance Corporation (FDIC) guaranteed senior notes issued by financial institutions under the Temporary Liquidity Guarantee Programs. We no longer own securities with an FDIC guarantee because this program ended on December 31, 2012.

The following table summarizes our financial assets with maturities of less than 90 days from the date of purchase included within cash and cash equivalents on the accompanying consolidated balance sheet:



	As of December 31,
(In millions)	2012		2011
Commercial paper	$	40.7	$	—
Repurchase agreements	67.4		8.8
Short-term debt securities	331.3		391.0
Total	$	439.4	$	399.8

The carrying values of our commercial paper, including accrued interest, repurchase agreements, and our short-term debt securities approximate fair value.

Summary of Contractual Maturities: Available-for-Sale Securities

The estimated fair value and amortized cost of our marketable debt securities available-for-sale by contractual maturity are summarized as follows:



	As of December 31, 2012				As of December 31, 2011
(In millions)	Estimated Fair Value		Amortized Cost		Estimated Fair Value		Amortized Cost
Due in one year or less	$	1,135.0	$	1,134.5	$	1,176.1	$	1,175.6
Due after one year through five years	1,744.3		1,741.2		1,251.6		1,251.4
Due after five years	292.4		292.3		165.2		165.8
Total available-for-sale securities	$	3,171.7	$	3,168.0	$	2,592.9	$	2,592.8

The average maturity of our marketable debt securities available-for-sale as of December 31, 2012 and 2011 was 14 months.

Proceeds from Marketable Debt Securities

The proceeds from maturities and sales of marketable debt securities and resulting realized gains and losses are summarized as follows:



	For the Years Ended December 31,
(In millions)	2012		2011		2010
Proceeds from maturities and sales	$	2,749.6	$	2,276.7	$	2,668.7
Realized gains	$	2.1	$	3.9	$	18.8
Realized losses	$	3.5	$	2.3	$	2.5

Proceeds were generally reinvested. Realized losses for the year ended December 31, 2012, primarily relate to sales of agency mortgage-backed securities. Realized losses for the year ended December 31, 2011, primarily relate to sales of government and corporate securities. Realized losses for the year ended December 31, 2010, primarily relate to the sale of agency mortgage-backed securities and corporate debt securities.

Strategic Investments

As of December 31, 2012 and 2011, our strategic investment portfolio was comprised of investments totaling $64.2 million and $62.8 million, respectively, which are included in investments and other assets in our accompanying consolidated balance sheets.

Our strategic investment portfolio includes investments in marketable equity securities of certain biotechnology companies and our investments in venture capital funds accounted for at fair value which totaled $29.3 million and $23.6 million as of December 31, 2012 and 2011, respectively. Our strategic investment portfolio also includes other equity investments in privately-held companies and additional investments in venture capital funds accounted for under the cost method. The carrying value of these investments totaled $34.9 million and $39.2 million, as of December 31, 2012 and 2011, respectively.

Net Gains, Impairments and Changes to Fair Value

During the years ended December 31, 2012, 2011, and 2010, we realized net gains, impairments and changes to fair value recorded through income of $6.5 million and $7.3 million and net losses of $20.1 million, respectively, on our strategic investment portfolio. Included within the net gains recognized during the year ended December 31, 2012, was a gain of $9.0 million recognized upon our acquisition of Stromedix as we previously held an equity interest. For a more detailed description of this transaction, please read Note 2, Acquisitions to these consolidated financial statements. In 2011, we sold four strategic investments for $40.6 million, which resulted in a net gain of $13.5 million. In 2010 we sold one strategic investment for $1.8 million, which resulted in an insignificant loss.

Impairments

During the years ended December 31, 2012, 2011, and 2010, we recognized impairment charges on our marketable equity securities of certain biotechnology companies, investments in venture capital funds accounted for under the cost method, investments in venture capital funds accounted for under the equity method and investments in privately-held companies totaling $5.5 million, $9.9 million, and $19.2 million, respectively.