Investments in Marketable Debt Securities (Tables)

6 Months Ended

Jun. 30, 2011

Marketable Debt Securities

Marketable debt securities at June 30, 2011 consisted of the following:

At June 30, 2011	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. tax-exempt securities	$	381.1	$	2.9			$	384.0
U.S. government and agency securities		2.5						2.5
U.S. corporate securities		41.2		.4				41.6
Non U.S. corporate securities		175.6		.4	$	.4		175.6
Non U.S. government securities		364.1		1.1		1.2		364.0
Other debt securities		85.1		.2				85.3
	$	1,049.6	$	5.0	$	1.6	$	1,053.0

Marketable debt securities at December 31, 2010 consisted of the following:

At December 31, 2010	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. tax-exempt securities	$	364.9	$	.8	$	.3	$	365.4
U.S. government and agency securities		2.7						2.7
U.S. corporate securities		27.3		.3				27.6
Non U.S. corporate securities		37.0						37.0
Other debt securities		17.8						17.8
	$	449.7	$	1.1	$	.3	$	450.5

Contractual Maturities of Debt Securities

Contractual maturities on these securities at June 30, 2011 were as follows:

Maturities:	Amortized Cost		Fair Value
Within one year	$	309.8	$	310.2
One to five years		739.8		742.8
	$	1,049.6	$	1,053.0