Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 27, 2013	Dec. 31, 2012
Allowances for billed receivables	$ 26	$ 33
Treasury stock (at cost), shares	62,194,678	57,418,645
L-3 Communications Holdings, Inc. [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares outstanding	89,047,037	90,433,743
L-3 Communications Corporation's [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100	100
Common stock, shares issued	100	100
Common stock, shares outstanding	100	100