Balance Sheet Accounts - Schedule of Other Noncurrent Assets (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Real estate held for entitlement and leasing	$ 105.5	$ 103.7
Deferred costs recoverable from the U.S. government	61.7	62.1
Receivable from Northrop Grumman Corporation for environmental remediation costs	30.0	34.5
Other	9.9	43.0
Other noncurrent assets	$ 207.1	$ 243.3

Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(d))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Name:	us-gaap_RealEstateInvestmentPropertyNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant