Balance Sheet Accounts and Supplemental Disclosures - Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Long-term contracts at average cost	$ 562.3	$ 551.9
Progress payments	(427.1)	(368.2)
Total long-term contract inventories	135.2	183.7
Total other inventories	1.2	1.4
Inventories	136.4	185.1
General and administrative costs incurred	238.4	257.4
Cumulative amount of general and administrative costs in long-term contract inventories estimated	$ 11.4	$ 21.1

Inventory For Long Term Contracts Or Programs At Average Cost

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- Definition

Inventory For Long-Term Contracts Or Programs, Net

+ References

No definition available.

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- Definition

Aggregate amount of general and administrative costs incurred in each period and charged to inventory.

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- Definition

Actual or estimated amount of general and administrative costs remaining in inventory.

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- Definition

Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section 35
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=68049868&loc=d3e3927-108312

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82887183&loc=d3e6676-107765

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Amount before valuation and LIFO reserves of other inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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- Definition

Amount of advances received from customers under long-term contracts which have been offset against inventories accounts at the balance sheet date.

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