Divestitures and Acquisitions - Unaudited Pro Forma Statements of Operations Data (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Business Acquisition [Line Items]
Pro forma net sales	$ 13,248	$ 13,479	$ 13,900
Pro forma income from continuing operations	789	879	867
Pro forma net income attributable to L-3	$ 811	$ 971	$ 998
Pro forma diluted earnings per share from continuing operations	$ 8.02	$ 8.23	$ 7.42
Pro forma diluted earnings per share	$ 8.31	$ 9.18	$ 8.63

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The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma income from continuing operations before changes in accounting and extraordinary items, net of tax effect, for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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Pro forma diluted earnings per share, which is commonly presented in initial public offerings.

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