Investments (Tables)

9 Months Ended

Sep. 30, 2011

Investments [Abstract]

Available-For-Sale Marketable Securities

September 30, 2011	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
U.S. government debt obligations	$	164.8	$	0.5	$	—		$	165.3
Corporate debt obligations guaranteed by FDIC		71.9		0.2		—			72.1
Corporate debt obligations		225.8		0.6		(1.9	)		224.5
Mortgage-backed debt obligations guaranteed by GNMA		94.6		0.5		(0.2	)		94.9
Certificates of deposit guaranteed by FDIC		2.0		—		—			2.0
Foreign government debt obligations		189.5		1.3		(0.1	)		190.7
Foreign corporate debt obligations guaranteed by foreign governments		86.3		0.2		(0.1	)		86.4
Total	$	834.9	$	3.3	$	(2.3	)	$	835.9
December 31, 2010
U.S. government debt obligations	$	259.0	$	0.1	$	(0.7	)	$	258.4
Corporate debt obligations guaranteed by FDIC		102.3		0.3		—			102.6
Corporate debt obligations		95.6		0.5		(0.2	)		95.9
Mortgage-backed debt obligations guaranteed by GNMA		175.5		0.8		(1.2	)		175.1
Certificates of deposit guaranteed by FDIC		3.3		—		—			3.3
Foreign government debt obligations		201.4		1.6		(0.9	)		202.1
Foreign corporate debt obligations guaranteed by foreign governments		87.8		0.6		(0.1	)		88.3
Total	$	924.9	$	3.9	$	(3.1	)	$	925.7

Maturities Of Available-For-Sale Marketable Securities

	Amortized Cost		Fair Value
Less than 12 months	$	245.0	$	245.5
Due in 1 to 5 years		497.5		497.7
Due after 5 years		92.4		92.7
Total	$	834.9	$	835.9

Investments In Marketable Securities With Unrealized Losses

	Unrealized Loss Less than 12 months					Unrealized Loss Greater than 12 months				Total
September 30, 2011	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Corporate debt obligations	$	132.8	$	(1.9	)	$	—	$	—	$	132.8	$	(1.9	)
Mortgage-backed debt obligations guaranteed by GNMA		23.1		(0.2	)		—		—		23.1		(0.2	)
Foreign government debt obligations		29.8		(0.1	)		—		—		29.8		(0.1	)
Foreign government debt obligations guaranteed by foreign governments		36.3		(0.1	)		—		—		36.3		(0.1	)
Total	$	222.0	$	(2.3	)	$	—	$	—	$	222.0	$	(2.3	)
December 31, 2010
U.S. government debt obligations	$	218.6	$	(0.7	)	$	—	$	—	$	218.6	$	(0.7	)
Corporate debt obligations		47.5		(0.2	)		—		—		47.5		(0.2	)
Mortgage-backed debt obligations guaranteed by GNMA		115.7		(1.2	)		—		—		115.7		(1.2	)
Foreign government debt obligations		92.9		(0.9	)		—		—		92.9		(0.9	)
Foreign government debt obligations guaranteed by foreign governments		32.6		(0.1	)		—		—		32.6		(0.1	)
Total	$	507.3	$	(3.1	)	$	—	$	—	$	507.3	$	(3.1	)

Gross Realized Gains And Losses Related To Fixed Income Investments

	Third Quarter						Nine Months
	9/30/11			10/1/10			9/30/11			10/1/10
Gross realized gains	$	1.7		$	6.3		$	3.1		$	14.2
Gross realized losses		(1.4	)		(1.8	)		(3.2	)		(2.2	)
Total	$	0.3		$	4.5		$	(0.1	)	$	12.0