Investments in Marketable Debt Securities (Tables)

9 Months Ended

Sep. 30, 2019

Available For Sale Securities [Abstract]

Marketable Debt Securities

Marketable debt securities at September 30, 2019 and December 31, 2018 consisted of the following:

	AMORTIZED		UNREALIZED		UNREALIZED		FAIR
At September 30, 2019	COST		GAINS		LOSSES		VALUE
U.S. tax-exempt securities	$	316.8	$	1.9	$	.3	$	318.4
U.S. corporate securities		160.6		2.0				162.6
U.S. government and agency securities		126.1		1.0				127.1
Non-U.S. corporate securities		303.0		2.6		.2		305.4
Non-U.S. government securities		65.0		.3				65.3
Other debt securities		127.8		1.3		.1		129.0
	$	1,099.3	$	9.1	$	.6	$	1,107.8

	AMORTIZED		UNREALIZED		UNREALIZED		FAIR
At December 31, 2018	COST		GAINS		LOSSES		VALUE
U.S. tax-exempt securities	$	326.0	$	.3	$	1.2	$	325.1
U.S. corporate securities		147.6		.2		.4		147.4
U.S. government and agency securities		98.9		.2		.4		98.7
Non-U.S. corporate securities		272.5		.4		1.6		271.3
Non-U.S. government securities		55.9		.1		.1		55.9
Other debt securities		122.6		.2		.8		122.0
	$	1,023.5	$	1.4	$	4.5	$	1,020.4

Marketable Debt Securities Continuous Unrealized Losses

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

	September 30, 2019				December 31, 2018
	LESS THAN		TWELVE MONTHS		LESS THAN		TWELVE MONTHS
	TWELVE MONTHS		OR GREATER		TWELVE MONTHS		OR GREATER
Fair value	$	134.4	$	66.6	$	252.8	$	397.9
Unrealized losses		.4		.2		.8		3.7

Contractual Maturities of Debt Securities

Contractual maturities on marketable debt securities at September 30, 2019 were as follows:

	AMORTIZED		FAIR
Maturities:	COST		VALUE
Within one year	$	273.5	$	273.8
One to five years		769.2		777.4
Six to ten years		20.0		20.0
More than ten years		36.6		36.6
	$	1,099.3	$	1,107.8