Investments in Marketable Debt Securities (Tables)

9 Months Ended

Sep. 30, 2016

Investments, Debt and Equity Securities [Abstract]

Marketable Debt Securities

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

At September 30, 2016	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. tax-exempt securities	$	499.1	$	1.2	$	.4	$	499.9
U.S. corporate securities		52.4		.4				52.8
U.S. government and agency securities		16.1		.2				16.3
Non-U.S. corporate securities		326.7		1.9				328.6
Non-U.S. government securities		98.7		1.1				99.8
Other debt securities		81.0		.5				81.5
	$	1,074.0	$	5.3	$	.4	$	1,078.9
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:

	September 30, 2016			December 31, 2015
	Less than Twelve Months		Twelve Months or Greater	Less than Twelve Months		Twelve Months or Greater
Fair value	$	292.5		$	579.0
Unrealized losses		.4			1.1

Contractual Maturities of Debt Securities

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

Maturities:	Amortized Cost		Fair Value
Within one year	$	284.7	$	284.9
One to five years		777.3		782.0
Six to ten years		2.0		2.0
More than ten years		10.0		10.0
	$	1,074.0	$	1,078.9