Balance Sheet Accounts and Supplemental Disclosures (Tables)

12 Months Ended

Dec. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Accounts Receivable

	As of December 31,
	2021		2020
	(In millions)
Billed	$	60.3	$	75.3
Other trade receivables	0.3		0.3
Accounts receivable	$	60.6	$	75.6

Schedule of Other Current Assets, net

	As of December 31,
	2021		2020
	(In millions)
Deferred costs recoverable from the U.S. government	$	37.4	$	41.0
Income tax receivable	22.1		46.9
Prepaid expenses	15.3		18.0
Inventories	10.0		10.0
Other	23.0		20.6
Other current assets	$	107.8	$	136.5

Schedule of Property, Plant and Equipment, net

	As of December 31,
	2021		2020
	(In millions)
Land	$	71.1	$	71.2
Buildings and improvements	503.0		433.4
Machinery and equipment, including capitalized software	499.1		471.3
Construction-in-progress	50.0		105.5
	1,123.2		1,081.4
Less: accumulated depreciation	(702.1)		(658.3)
Property, plant and equipment, net	$	421.1	$	423.1

Schedule of Intangible Assets

	As of December 31, 2021
	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
	(In millions)
Customer related	$	87.2	$	81.3	$	5.9
Intellectual property\trade secrets	34.2		22.3		11.9
Trade name	21.0		6.1		14.9
Acquired technology	19.2		17.0		2.2
Intangible assets	$	161.6	$	126.7	$	34.9

	As of December 31, 2020
	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
	(In millions)
Customer related	$	87.2	$	75.3	$	11.9
Intellectual property\trade secrets	34.2		19.7		14.5
Trade name	21.0		5.4		15.6
Acquired technology	19.2		16.4		2.8
Intangible assets	$	161.6	$	116.8	$	44.8

Schedule of Future Amortization Expense for Intangible Assets

Future amortization expense for the five succeeding years is estimated to be as follows:

Year Ending December 31,	Future Amortization Expense
	(In millions)
2022	$	6.6
2023	6.1
2024	4.8
2025	3.7
2026	2.1
	$	23.3

Schedule of Other Noncurrent Assets, net

	As of December 31,
	2021		2020
	(In millions)
Real estate held for entitlement and leasing	$	103.7	$	101.8
Receivable from Northrop Grumman Corporation for environmental remediation costs	34.5		40.5
Deferred costs recoverable from the U.S. government	62.1		54.7
Other	43.0		57.8
Other noncurrent assets	$	243.3	$	254.8

Schedule of Other Current Liabilities

	As of December 31,
	2021		2020
	(In millions)
Accrued compensation and employee benefits	$	122.0	$	118.0
Dividends payable	1.7		447.8
Other	49.0		43.9
Other current liabilities	$	172.7	$	609.7

Schedule of Accumulated Other Comprehensive Loss, Net of Income Taxes

The following table presents the changes in accumulated other comprehensive loss by components, net of income taxes:

	Actuarial Losses, Net		Prior Service Credits (Costs), Net		Total
	(In millions)
December 31, 2019	$	(236.4)	$	(0.1)	$	(236.5)
Actuarial losses, net of income taxes	(31.5)		—		(31.5)
Amortization of net actuarial losses and prior service credits, net of income taxes	40.3		0.1		40.4
December 31, 2020	(227.6)		—		(227.6)
Actuarial gains, net of income taxes	80.5		—		80.5
Amortization of net actuarial losses and prior service costs, net of income taxes	46.0		0.1		46.1
December 31, 2021	$	(101.1)	$	0.1	$	(101.0)