Investments

6 Months Ended

Jun. 30, 2013

Investments Debt And Equity Securities [Abstract]

Investments

5. Investments

We invest in short and long-term investments classified as available-for-sale securities. Information regarding our investments is as follows (in millions):

	Amortized		Gross Unrealized
	Cost		Gains		Losses			Fair value
As of June 30, 2013
Corporate debt securities	$	392.7	$	0.1	$	(0.8	)	$	392.0
U.S. government and agency debt securities		271.6		0.1		(0.1	)		271.6
Commercial paper		49.0		—		—			49.0
Certificates of deposit		87.4		0.1		—			87.5
Total short and long-term investments	$	800.7	$	0.3	$	(0.9	)	$	800.1
As of December 31, 2012
Corporate debt securities	$	383.6	$	0.3	$	(0.1	)	$	383.8
U.S. government and agency debt securities		295.8		0.1		—			295.9
Foreign government debt securities		5.0		—		—			5.0
Commercial paper		138.7		—		—			138.7
Certificates of deposit		92.2		0.1		—			92.3
Total short and long-term investments	$	915.3	$	0.5	$	(0.1	)	$	915.7

Unrealized gains and losses on these investments are recorded in OCI in our condensed consolidated balance sheet.

The following table shows the fair value and gross unrealized losses for all available-for-sale securities in an unrealized loss position deemed to be temporary (in millions):

	June 30, 2013					December 31, 2012
	Fair Value		Unrealized Losses			Fair value		Unrealized Losses
Corporate debt securities	$	251.6	$	(0.8	)	$	144.2	$	(0.1	)
U.S. government and agency debt securities		161.5		(0.1	)		—		—
Total	$	413.1	$	(0.9	)	$	144.2	$	(0.1	)

All securities in the table above have been in an unrealized loss position for less than twelve months. A total of 147 securities were in an unrealized loss position as of June 30, 2013.

The unrealized losses on our investments in corporate debt securities were caused by increases in interest yields in the global credit markets. We believe the unrealized losses associated with our available-for-sale securities as of June 30, 2013 are temporary because we do not intend to sell these investments, and we do not believe we will be required to sell them before recovery of their amortized cost basis.

The amortized cost and fair value of our available-for-sale fixed-maturity securities by contractual maturity are as follows (in millions):

	June 30, 2013
	Amortized Cost		Fair Value
Due in one year or less	$	525.9	$	525.9
Due after one year through two years		274.8		274.2
Total	$	800.7	$	800.1