Investments in Marketable Debt Securities (Tables)

6 Months Ended

Jun. 30, 2016

Investments, Debt and Equity Securities [Abstract]

Marketable Debt Securities

Marketable debt securities at June 30, 2016 and December 31, 2015 consisted of the following:

At June 30, 2016	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. tax-exempt securities	$	490.3	$	2.7			$	493.0
U.S. corporate securities		100.9		.5	$	.1		101.3
U.S. government and agency securities		16.2		.3				16.5
Non-U.S. corporate securities		554.6		2.9		.1		557.4
Non-U.S. government securities		154.1		1.8				155.9
Other debt securities		101.6		.6				102.2
	$	1,417.7	$	8.8	$	.2	$	1,426.3
At December 31, 2015	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. tax-exempt securities	$	505.0	$	.7	$	.3	$	505.4
U.S. corporate securities		76.7		.1		.1		76.7
U.S. government and agency securities		15.7		.1		.1		15.7
Non-U.S. corporate securities		585.6		1.8		.4		587.0
Non-U.S. government securities		192.7		1.1		.1		193.7
Other debt securities		69.6		.1		.1		69.6
	$	1,445.3	$	3.9	$	1.1	$	1,448.1

Marketable Debt Securities Continuous Unrealized Losses

Marketable debt securities with continuous unrealized losses and their related fair values were as follows:

	June 30, 2016			December 31, 2015
	Less than           Twelve Months		Twelve Months or Greater	Less than Twelve Months		Twelve Months or Greater
Fair value	$	213.4		$	579.0
Unrealized losses		.2			1.1

Contractual Maturities of Debt Securities

Contractual maturities on marketable debt securities at June 30, 2016 were as follows:

Maturities:	Amortized Cost		Fair Value
Within one year	$	436.3	$	436.8
One to five years		981.3		989.4
Six to ten years		.1		.1
	$	1,417.7	$	1,426.3