Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 432.8	$ 535.0
Marketable securities	20.0	20.0
Accounts receivable	170.1	64.5
Contract assets	266.0	268.1
Other current assets, net	156.7	129.1
Total Current Assets	1,045.6	1,016.7
Noncurrent Assets
Property, plant and equipment, net	352.8	359.0
Recoverable environmental remediation costs	228.1	231.1
Deferred income taxes	253.1	145.8
Goodwill	161.3	161.3
Intangible assets	82.1	85.5
Other noncurrent assets, net	262.9	259.3
Total Noncurrent Assets	1,340.3	1,242.0
Total Assets	2,385.9	2,258.7
Current Liabilities
Current portion of long-term debt	27.7	25.0
Accounts payable	133.4	100.9
Reserves for environmental remediation costs	36.4	35.2
Contract liabilities	212.6	276.8
Other current liabilities	267.6	156.9
Total Current Liabilities	677.7	594.8
Noncurrent Liabilities
Long-term debt	586.3	591.4
Reserves for environmental remediation costs	302.0	306.2
Pension benefits	480.3	492.8
Other noncurrent liabilities	170.4	171.1
Total Noncurrent Liabilities	1,539.0	1,561.5
Total Liabilities	2,216.7	2,156.3
Commitments and contingencies (Note 8)
Stockholders’ Equity
Preference stock, par value of $1.00; 15.0 million shares authorized; none issued or outstanding	0.0	0.0
Common stock, par value of $0.10; 150.0 million shares authorized; 73.8 million shares issued and outstanding as of March 31, 2018; 73.6 million shares issued and outstanding as of December 31, 2017	7.4	7.4
Other capital	505.8	503.1
Treasury stock at cost, 3.5 million shares as of March 31, 2018 and December 31, 2017	(64.5)	(64.5)
Accumulated deficit	(19.4)	(71.0)
Accumulated other comprehensive loss, net of income taxes	(260.1)	(272.6)
Total Stockholders’ Equity	169.2	102.4
Total Liabilities and Stockholders’ Equity	$ 2,385.9	$ 2,258.7