Revision of Previously Issued Financial Statements - Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Jan. 01, 2021	Dec. 31, 2020	Jan. 01, 2020	Jan. 01, 2019
Reclassification [Line Items]
Cash and cash equivalents	$ 334.5		$ 700.4
Restricted cash	3.0		3.0
Marketable securities	9.2		10.6
Accounts receivable	134.0		60.6
Contract assets	403.3		354.2
Other current assets	117.7		99.5
Total Current Assets	1,001.7		1,228.3
Right-of-use assets	49.5		52.6
Property, plant and equipment, net	413.3		421.1
Recoverable environmental remediation costs	221.5		226.2
Deferred income taxes	189.3		55.6
Goodwill	161.4		161.4
Intangible assets	29.8		34.9
Other noncurrent assets	207.1		243.3
Total Noncurrent Assets	1,271.9		1,195.1
Total Assets	2,273.6		2,423.4
Current portion of long-term debt	14.7		166.7
Accounts payable	117.0		132.2
Reserves for environmental remediation costs	39.5		37.7
Contract liabilities	351.1		366.5
Other current liabilities	280.6		172.7
Total Current Liabilities	802.9		875.8
Long-term debt	292.1		294.6
Reserves for environmental remediation costs	253.9		258.7
Pension benefits	223.1		255.9
Operating lease liabilities	40.1		41.3
Other noncurrent liabilities	136.4		173.8
Total Noncurrent Liabilities	945.6		1,024.3
Total Liabilities	1,748.5		1,900.1
Common stock	8.0		8.0
Other capital	505.1		578.1			$ 20.9		$ 20.9	$ 20.9
Treasury stock at cost			(64.4)
Retained earnings	160.4		102.6			$ (7.8)		$ 8.0	$ 7.9
Accumulated other comprehensive loss, net of income taxes	(85.4)		(101.0)
Total Stockholders’ Equity	525.1	$ 574.1	523.3	$ 387.1	$ 326.0		$ 220.4
Total Liabilities and Stockholders’ Equity	$ 2,273.6		2,423.4
Previously Reported
Reclassification [Line Items]
Cash and cash equivalents			700.4
Restricted cash			3.0
Marketable securities			10.6
Accounts receivable			60.6
Contract assets			354.2
Other current assets			107.8
Total Current Assets			1,236.6
Right-of-use assets			52.6
Property, plant and equipment, net			421.1
Recoverable environmental remediation costs			226.2
Deferred income taxes			57.5
Goodwill			161.4
Intangible assets			34.9
Other noncurrent assets			243.3
Total Noncurrent Assets			1,197.0
Total Assets			2,433.6
Current portion of long-term debt			166.7
Accounts payable			132.2
Reserves for environmental remediation costs			37.7
Contract liabilities			366.5
Other current liabilities			172.7
Total Current Liabilities			875.8
Long-term debt			294.6
Reserves for environmental remediation costs			258.7
Pension benefits			255.9
Operating lease liabilities			41.3
Other noncurrent liabilities			173.8
Total Noncurrent Liabilities			1,024.3
Total Liabilities			1,900.1
Common stock			8.0
Other capital			599.0
Treasury stock at cost			(64.4)
Retained earnings			91.9
Accumulated other comprehensive loss, net of income taxes			(101.0)
Total Stockholders’ Equity			533.5	400.3
Total Liabilities and Stockholders’ Equity			2,433.6
Adjustments
Reclassification [Line Items]
Cash and cash equivalents			0.0
Restricted cash			0.0
Marketable securities			0.0
Accounts receivable			0.0
Contract assets			0.0
Other current assets			(8.3)
Total Current Assets			(8.3)
Right-of-use assets			0.0
Property, plant and equipment, net			0.0
Recoverable environmental remediation costs			0.0
Deferred income taxes			(1.9)
Goodwill			0.0
Intangible assets			0.0
Other noncurrent assets			0.0
Total Noncurrent Assets			(1.9)
Total Assets			(10.2)
Current portion of long-term debt			0.0
Accounts payable			0.0
Reserves for environmental remediation costs			0.0
Contract liabilities			0.0
Other current liabilities			0.0
Total Current Liabilities			0.0
Long-term debt			0.0
Reserves for environmental remediation costs			0.0
Pension benefits			0.0
Operating lease liabilities			0.0
Other noncurrent liabilities			0.0
Total Noncurrent Liabilities			0.0
Total Liabilities			0.0
Common stock			0.0
Other capital			(20.9)
Treasury stock at cost			0.0
Retained earnings			10.7
Accumulated other comprehensive loss, net of income taxes			0.0
Total Stockholders’ Equity			(10.2)	$ (13.2)
Total Liabilities and Stockholders’ Equity			$ (10.2)