Investments in Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2023

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

Marketable securities at September 30, 2023 and December 31, 2022 consisted of the following:

			UNREALIZED		UNREALIZED		FAIR
At September 30, 2023	COST		GAINS		LOSSES		VALUE
Marketable debt securities
U.S. tax-exempt securities	$	293.0			$	8.1	$	284.9
U.S. taxable municipal / non-U.S. provincial bonds		249.3				9.0		240.3
U.S. corporate securities		354.4				10.2		344.2
U.S. government and agency securities		151.6				4.4		147.2
Non-U.S. corporate securities		510.4				14.3		496.1
Non-U.S. government securities		134.2	$	.2		2.2		132.2
Other debt securities		100.1				4.3		95.8
Marketable equity securities		10.0				7.6		2.4
Total marketable securities	$	1,803.0	$	.2	$	60.1	$	1,743.1

			UNREALIZED		UNREALIZED		FAIR
At December 31, 2022	COST		GAINS		LOSSES		VALUE
Marketable debt securities
U.S. tax-exempt securities	$	452.8	$	.5	$	8.2	$	445.1
U.S. taxable municipal / non-U.S. provincial bonds		191.6				10.8		180.8
U.S. corporate securities		262.5		.1		11.6		251.0
U.S. government and agency securities		118.0		.1		3.1		115.0
Non-U.S. corporate securities		467.9				17.9		450.0
Non-U.S. government securities		78.9		.2		2.7		76.4
Other debt securities		99.4				4.7		94.7
Marketable equity securities		10.0				8.8		1.2
Total marketable securities	$	1,681.1	$	.9	$	67.8	$	1,614.2

Marketable Debt Securities Continuous Unrealized Losses

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

	September 30, 2023				December 31, 2022
	LESS THAN		TWELVE MONTHS		LESS THAN		TWELVE MONTHS
	TWELVE MONTHS		OR GREATER		TWELVE MONTHS		OR GREATER
Unrealized losses	$	11.7	$	40.8	$	21.5	$	37.5
Fair value		706.6		850.1		889.2		608.4

Contractual Maturities of Debt Securities

Contractual maturities of marketable debt securities at September 30, 2023 were as follows:

	AMORTIZED		FAIR
	COST		VALUE
Within one year	$	449.0	$	441.5
One to five years		1,330.9		1,287.6
Six to ten years		.9		.9
More than ten years		12.2		10.7
	$	1,793.0	$	1,740.7