Investments in Marketable Debt Securities (Tables)

3 Months Ended

Mar. 31, 2019

Available For Sale Securities [Abstract]

Marketable Debt Securities

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

	AMORTIZED		UNREALIZED		UNREALIZED		FAIR
At March 31, 2019	COST		GAINS		LOSSES		VALUE
U.S. tax-exempt securities	$	304.2	$	1.1	$	.4	$	304.9
U.S. corporate securities		162.4		1.1		.1		163.4
U.S. government and agency securities		110.9		.3		.2		111.0
Non-U.S. corporate securities		301.8		1.5		.5		302.8
Non-U.S. government securities		74.2		.2				74.4
Other debt securities		125.0		.6		.5		125.1
	$	1,078.5	$	4.8	$	1.7	$	1,081.6

	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:

	March 31, 2019				December 31, 2018
	LESS THAN		TWELVE MONTHS		LESS THAN		TWELVE MONTHS
	TWELVE MONTHS		OR GREATER		TWELVE MONTHS		OR GREATER
Fair value	$	53.5	$	370.3	$	252.8	$	397.9
Unrealized losses				1.7		.8		3.7

Contractual Maturities of Debt Securities

Contractual maturities on marketable debt securities at March 31, 2019 were as follows:

	AMORTIZED		FAIR
Maturities:	COST		VALUE
Within one year	$	319.1	$	318.8
One to five years		740.7		744.1
Six to ten years		3.7		3.7
More than ten years		15.0		15.0
	$	1,078.5	$	1,081.6