Debt - Information Regarding Outstanding Series of Senior Subordinated Note (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 26, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Net Cash Proceeds	$ 996
L-3 Communications Corporation [Member]
Debt Instrument [Line Items]
Net Cash Proceeds	988
Redemption price as percentage of principal amount	100.00%
Senior notes redemption price	101.00%
L-3 Communications Corporation [Member] | 1.50% Senior Notes due 2017 [Member]
Debt Instrument [Line Items]
Interest rate on Senior Notes	1.50%	1.50%
Senior Notes due	May 28, 2017
Net Cash Proceeds	347
L-3 Communications Corporation [Member] | 3.95% Senior Notes due 2024 [Member]
Debt Instrument [Line Items]
Interest rate on Senior Notes	3.95%	3.95%
Senior Notes due	May 28, 2024
Net Cash Proceeds	$ 641
L-3 Communications Corporation [Member] | Minimum [Member] | 3.95% Senior Notes due 2024 [Member]
Debt Instrument [Line Items]
Senior Notes due	Feb. 28, 2024