Debt - Components of Debt and Reconciliation to Carrying Amount of Long-Term Debt (Parenthetical) (Detail) (USD $)	9 Months Ended		0 Months Ended				0 Months Ended				0 Months Ended				0 Months Ended				0 Months Ended				0 Months Ended				0 Months Ended
	Sep. 26, 2014	Sep. 26, 2014 CODES Due 2035 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 3.95% Senior Notes due 2016 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 3.95% Senior Notes due 2016 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 3.95% Senior Notes due 2016 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 3.95% Senior Notes due 2016 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 1.50% Senior Notes due 2017 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 1.50% Senior Notes due 2017 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 1.50% Senior Notes due 2017 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 1.50% Senior Notes due 2017 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 5.20% Senior Notes due 2019 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 5.20% Senior Notes due 2019 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 5.20% Senior Notes due 2019 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 5.20% Senior Notes due 2019 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 4.75% Senior Notes due 2020 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 4.75% Senior Notes due 2020 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 4.75% Senior Notes due 2020 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 4.75% Senior Notes due 2020 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 4.95% Senior Notes due 2021 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 4.95% Senior Notes due 2021 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 4.95% Senior Notes due 2021 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 4.95% Senior Notes due 2021 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 3.95% Senior Notes due 2024 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 3.95% Senior Notes due 2024 [Member]	Sep. 26, 2014 L-3 Communications Corporation [Member] 3.95% Senior Notes due 2024 [Member]	Dec. 31, 2013 L-3 Communications Corporation [Member] 3.95% Senior Notes due 2024 [Member]	Sep. 26, 2014 L-3 Communications Holdings, Inc. [Member] CODES Due 2035 [Member]	Dec. 31, 2013 L-3 Communications Holdings, Inc. [Member] CODES Due 2035 [Member]	Sep. 26, 2014 L-3 Communications Holdings, Inc. [Member] CODES Due 2035 [Member]	Dec. 31, 2013 L-3 Communications Holdings, Inc. [Member] CODES Due 2035 [Member]
Debt Instrument [Line Items]
Interest rate on Senior Notes		3.00%			3.95%	3.95%			1.50%	1.50%			5.20%	5.20%			4.75%	4.75%			4.95%	4.95%			3.95%	3.95%			3.00%	3.00%
Debt instrument maturity period			2016	2016			2017	2017			2019	2019			2020	2020			2021	2021			2024	2024			2035	2035
Aggregate borrowings and repayments under the Amended and Restated Revolving Credit Facility	$ 1,367,000,000
Borrowings under Amended and Restated Revolving Credit Facility	$ 1,000,000,000
Revolving credit facility expiration date	Feb. 03, 2017