Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 514.7	$ 535.0
Marketable securities	44.9	20.0
Accounts receivable	134.6	64.5
Contract assets	253.1	268.1
Other current assets, net	123.2	129.1
Total Current Assets	1,070.5	1,016.7
Noncurrent Assets
Property, plant and equipment, net	357.8	359.0
Recoverable environmental remediation costs	225.8	231.1
Deferred income taxes	255.5	145.8
Goodwill	161.3	161.3
Intangible assets	78.7	85.5
Other noncurrent assets, net	260.5	259.3
Total Noncurrent Assets	1,339.6	1,242.0
Total Assets	2,410.1	2,258.7
Current Liabilities
Current portion of long-term debt	30.4	25.0
Accounts payable	104.1	100.9
Reserves for environmental remediation costs	34.6	35.2
Contract liabilities	185.3	276.8
Other current liabilities	313.0	156.9
Total Current Liabilities	667.4	594.8
Noncurrent Liabilities
Long-term debt	581.0	591.4
Reserves for environmental remediation costs	299.1	306.2
Pension benefits	467.8	492.8
Other noncurrent liabilities	174.7	171.1
Total Noncurrent Liabilities	1,522.6	1,561.5
Total Liabilities	2,190.0	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; 73.9 million shares issued and outstanding as of June 30, 2018; 73.6 million shares issued and outstanding as of December 31, 2017	7.4	7.4
Other capital	509.4	503.1
Treasury stock at cost, 3.5 million shares as of June 30, 2018 and December 31, 2017	(64.5)	(64.5)
Retained earnings (accumulated deficit)	15.4	(71.0)
Accumulated other comprehensive loss, net of income taxes	(247.6)	(272.6)
Total Stockholders’ Equity	220.1	102.4
Total Liabilities and Stockholders’ Equity	$ 2,410.1	$ 2,258.7