Marketable Securities Held in Trusts (Tables)

9 Months Ended

Sep. 30, 2020

Investments, Debt and Equity Securities [Abstract]

The estimated fair value of the investments in the RCRA Trusts as of September 30, 2020 and December 31, 2019 are as follows:


	September 30, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Level 1
Cash and cash equivalents	$	8.6	$	—	$	—	$	8.6
Level 2
Corporate debt securities	191.2		13.1		(0.2)		204.1
Municipal bonds	191.5		7.9		(0.6)		198.8
U.S. government bonds	299.4		7.4		—		306.8
Total	$	690.7	$	28.4	$	(0.8)	$	718.3

	December 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Level 1
Cash and cash equivalents	$	3.4	$	—	$	—	$	3.4
Level 2
Corporate debt securities	194.2		5.8		(0.1)		199.9
Municipal bonds	188.3		4.4		(0.4)		192.3
U.S. government bonds	280.6		3.2		(2.5)		281.3
Total	$	666.5	$	13.4	$	(3.0)	$	676.9

Fair value of available-for-sale debt securities in an unrealized loss position

The following tables show gross unrealized losses and fair values of the RCRA Trusts' available-for-sale securities that have been in a continuous unrealized loss position deemed to be temporary as of September 30, 2020 and December 31, 2019:


	September 30, 2020				December 31, 2019
(in millions)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Securities that have been in a continuous loss position for less than 12 months:
Corporate debt securities	$	9.2	$	(0.2)	$	17.9	$	—
Municipal bonds	25.6		—		11.7		(0.1)
U.S. government bonds	5.2		(0.5)		195.4		(2.5)
	$	40.0	$	(0.7)	$	225.0	$	(2.6)
Securities that have been in a continuous loss position for more than 12 months:


Corporate debt securities	$	—	$	—	$	20.7	$	(0.1)
Municipal bonds	5.4		(0.1)		14.7		(0.3)
U.S. government bonds	—		—		—		—
	$	5.4	$	(0.1)	$	35.4	$	(0.4)

Schedule of maturity dates for debt securities

The following table summarizes the balance by contractual maturity of the available-for-sale debt securities invested by the RCRA Trusts as of September 30, 2020. Actual maturities may differ from contractual maturities because the issuers of the securities may have the right to prepay obligations before the underlying contracts mature.


	September 30, 2020
Due in one year or less	$	28.8
Due after one year through five years	333.5
Due after five years through ten years	302.8
Due after ten years	44.6
Total debt securities	$	709.7