Balance Sheet Accounts

3 Months Ended

Mar. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

a. Fair Value of Financial Instruments

Financial instruments are classified using a three-tiered fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.



			Fair value measurement as of March 31, 2020
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)
	(In millions)
Money market funds	$	652.9	$	652.9	$	—	$	—
Registered investment companies	3.3		3.3		—		—
Commercial paper	15.0		—		15.0		—
Total	$	671.2	$	656.2	$	15.0	$	—



			Fair value measurement as of December 31, 2019
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)
	(In millions)
Money market funds	$	626.0	$	626.0	$	—	$	—
Registered investment companies	3.7		3.7		—		—
Commercial paper	99.9		—		99.9
Total	$	729.6	$	629.7	$	99.9	$	—

As of March 31, 2020 and December 31, 2019, the total estimated fair value for commercial paper was classified as cash and cash equivalents as the remaining maturity at date of purchase was less than three months.

The carrying amounts of certain of the Company’s financial instruments, including cash and cash equivalents, restricted cash, accounts receivable, accounts payable, accrued compensation, and other accrued liabilities, approximate fair value because of their short maturities.

The following table summarizes the estimated fair value and principal amount for outstanding debt obligations excluding finance lease obligations:



	Fair Value				Principal Amount
	March 31, 2020		December 31, 2019		March 31, 2020		December 31, 2019
	(In millions)
Term loan	$	299.9	$	328.1	$	323.8	$	328.1
2¹/₄% Notes	488.2		546.0		300.0		300.0
Total	$	788.1	$	874.1	$	623.8	$	628.1

The fair value of the 2¼% Notes was determined using broker quotes that are based on open markets for the Company's debt securities (Level 2 securities). The fair value of the term loan at March 31, 2020, was estimated based on a third-party model used to derive a relative value price using comparable corporate loans within the same industry, credit quality, and currency. At December 31, 2019, the term loan carrying value approximated fair value.

b. Accounts Receivable, net



	March 31, 2020			December 31, 2019
	(In millions)
Billed receivables under long-term contracts	$	152.5		$	122.9
Reserve on billed trade receivables	(1.0		)	(10.6		)
Other trade receivables	0.2			0.2
Accounts receivable, net	$	151.7		$	112.5

c. Other Current Assets, net



	March 31, 2020		December 31, 2019
	(In millions)
Deferred costs recoverable from the U.S. government	$	46.9	$	47.1
Income taxes receivable	36.2		43.4
Inventories	18.0		24.0
Prepaid expenses	13.4		13.9
Other	22.9		17.4
Other current assets, net	$	137.4	$	145.8

d. Property, Plant and Equipment, net



	March 31, 2020			December 31, 2019
	(In millions)
Land	$	71.2		$	71.2
Buildings and improvements	436.2			434.9
Machinery and equipment, including capitalized software	459.4			488.2
Construction-in-progress	67.1			70.2
	1,033.9			1,064.5
Less: accumulated depreciation	(630.7		)	(654.6		)
Property, plant and equipment, net	$	403.2		$	409.9

e. Other Noncurrent Assets, net



	March 31, 2020		December 31, 2019
	(In millions)
Real estate held for entitlement and leasing	$	100.4	$	100.3
Deferred costs recoverable from the U.S. government	55.9		54.8
Receivable from Northrop Grumman Corporation for environmental remediation costs	45.0		46.5
Other	50.2		54.0
Other noncurrent assets, net	$	251.5	$	255.6

f. Other Current Liabilities



	March 31, 2020		December 31, 2019
	(In millions)
Accrued compensation and employee benefits	$	90.0	$	103.1
Other	44.4		52.4
Other current liabilities	$	134.4	$	155.5

g. Treasury Stock

During the three months ended March 31, 2020, the Company repurchased less than 0.1 million of its common shares at a cost of $0.5 million. The Company reflects stock repurchases in its financial statements on a "settlement" basis.