Investments in Marketable Debt Securities

12 Months Ended

Dec. 31, 2020

Available For Sale Securities [Abstract]

Investments in Marketable Debt Securities

C. INVESTMENTS IN MARKETABLE DEBT SECURITIES

Marketable debt securities consisted of the following at December 31:

	AMORTIZED		UNREALIZED		UNREALIZED		FAIR
2020	COST		GAINS		LOSSES		VALUE
U.S. tax-exempt securities	$	388.1	$	4.4	$	.1	$	392.4
U.S. corporate securities		229.6		3.3				232.9
U.S. government and agency securities		92.1		2.3				94.4
Non-U.S. corporate securities		406.0		5.5				411.5
Non-U.S. government securities		77.0		.5				77.5
Other debt securities		216.9		3.4				220.3
	$	1,409.7	$	19.4	$	.1	$	1,429.0

	AMORTIZED		UNREALIZED		UNREALIZED		FAIR
2019	COST		GAINS		LOSSES		VALUE
U.S. tax-exempt securities	$	318.1	$	2.2	$	.1	$	320.2
U.S. corporate securities		163.8		1.9				165.7
U.S. government and agency securities		128.4		.9				129.3
Non-U.S. corporate securities		347.7		2.3		.2		349.8
Non-U.S. government securities		72.3		.2		.1		72.4
Other debt securities		123.7		1.1		.1		124.7
	$	1,154.0	$	8.6	$	.5	$	1,162.1

The cost of marketable debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Amortization, accretion, interest and dividend income and realized gains and losses are included in investment income. The cost of securities sold is based on the specific identification method. Gross realized gains were $2.7, $1.3 and $1.1, and gross realized losses were $.3, $.4 and $.8 for the years ended December 31, 2020, 2019 and 2018, respectively.

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

At December 31,	2020				2019
	LESS THAN TWELVE MONTHS		TWELVE MONTHS OR GREATER		LESS THAN TWELVE MONTHS		TWELVE MONTHS OR GREATER
Fair value	$	81.1	$	1.3	$	177.0	$	31.4
Unrealized losses		.1				.4		.1

The unrealized losses on the investments above were due to higher yields on certain securities. The Company did not identify any indicators of a credit loss in its assessments. Accordingly, no allowance for credit losses was recorded at December 31, 2020 and December 31, 2019. The Company does not currently intend, and it is more likely than not, that it will not be required to sell the investment securities before recovery of the unrealized losses. The Company expects that the contractual principal and interest will be received on the investment securities. 

Contractual maturities on marketable debt securities at December 31, 2020 were as follows:

	AMORTIZED		FAIR
Maturities:	COST		VALUE
Within one year	$	313.9	$	315.7
One to five years		1,088.6		1,106.1
Six to ten years		5.2		5.2
More than ten years		2.0		2.0
	$	1,409.7	$	1,429.0

Marketable debt securities included nil and $49.7 of variable rate demand obligations (VRDOs) at December 31, 2020 and 2019, respectively. VRDOs are debt instruments with long-term scheduled maturities which have interest rates that reset periodically. Actual maturities of VRDOs may differ from contractual maturities because these securities may be sold when interest rates are reset.