Description of Business	9 Months Ended
Sep. 26, 2014
Accounting Policies [Abstract]
Description of Business	1. Description of Business L-3 Communications Holdings, Inc. derives all of its operating income and cash flows from its wholly-owned subsidiary, L-3 Communications Corporation (L-3 Communications). L-3 Communications Holdings, Inc. (L-3 Holdings and, together with its subsidiaries, referred to herein as L-3 or the Company) is a prime contractor in aerospace systems and national security solutions. L-3 is also a leading provider of a broad range of communication and electronic systems and products used on military and commercial platforms. The Company’s customers include the United States (U.S.) Department of Defense (DoD) and its prime contractors, U.S. government intelligence agencies, the U.S. Department of Homeland Security (DHS), U.S. Department of State (DoS), allied international governments, and domestic and international commercial customers. In the first quarter of 2014, the Company completed a realignment of its segments to better align its organizational structure with customer priorities and increase operational efficiencies. As a result of the realignment, L-3’s structure consists of four segments: (1) Electronic Systems, (2) Aerospace Systems, (3) Communication Systems and (4) National Security Solutions (NSS). Electronic Systems provides a broad range of components, products, subsystems, systems and related services for military and commercial customers in several niche markets across several business areas. These business areas include precision engagement & training, sensor systems, power & propulsion systems, marine systems international, aviation products, warrior systems and security & detection systems. Aerospace Systems delivers integrated solutions for the global Intelligence, Surveillance and Reconnaissance (ISR) market and provides modernization, upgrade, sustainment, and maintenance and logistics support for a wide variety of aircraft and ground systems. Communication Systems delivers products and services for the global communications market, specializing in strategic and tactical airborne, space, ground and sea-based communication systems. NSS provides cybersecurity solutions, high-performance computing, enterprise information technology (IT) services, analytics and intelligence analysis to the DoD, U.S. Government intelligence agencies, federal civilian agencies and allied international governments. Financial information with respect to the Company’s segments is included in Note 22 to the unaudited condensed consolidated financial statements and Note 23 to the audited consolidated financial statements included in its Form 10-K/A. Financial information for the quarterly and year-to-date periods ended September 27, 2013 in these unaudited condensed consolidated financial statements has been revised for the segment realignment discussed above and the revision to previously issued financial statements discussed in Note 3 to the unaudited condensed consolidated financial statements.

1. Description of Business

L-3 Communications Holdings, Inc. derives all of its operating income and cash flows from its wholly-owned subsidiary, L-3 Communications Corporation (L-3 Communications). L-3 Communications Holdings, Inc. (L-3 Holdings and, together with its subsidiaries, referred to herein as L-3 or the Company) is a prime contractor in aerospace systems and national security solutions. L-3 is also a leading provider of a broad range of communication and electronic systems and products used on military and commercial platforms. The Company’s customers include the United States (U.S.) Department of Defense (DoD) and its prime contractors, U.S. government intelligence agencies, the U.S. Department of Homeland Security (DHS), U.S. Department of State (DoS), allied international governments, and domestic and international commercial customers.

In the first quarter of 2014, the Company completed a realignment of its segments to better align its organizational structure with customer priorities and increase operational efficiencies. As a result of the realignment, L-3’s structure consists of four segments: (1) Electronic Systems, (2) Aerospace Systems, (3) Communication Systems and (4) National Security Solutions (NSS). Electronic Systems provides a broad range of components, products, subsystems, systems and related services for military and commercial customers in several niche markets across several business areas. These business areas include precision engagement & training, sensor systems, power & propulsion systems, marine systems international, aviation products, warrior systems and security & detection systems. Aerospace Systems delivers integrated solutions for the global Intelligence, Surveillance and Reconnaissance (ISR) market and provides modernization, upgrade, sustainment, and maintenance and logistics support for a wide variety of aircraft and ground systems. Communication Systems delivers products and services for the global communications market, specializing in strategic and tactical airborne, space, ground and sea-based communication systems. NSS provides cybersecurity solutions, high-performance computing, enterprise information technology (IT) services, analytics and intelligence analysis to the DoD, U.S. Government intelligence agencies, federal civilian agencies and allied international governments.

Financial information with respect to the Company’s segments is included in Note 22 to the unaudited condensed consolidated financial statements and Note 23 to the audited consolidated financial statements included in its Form 10-K/A. Financial information for the quarterly and year-to-date periods ended September 27, 2013 in these unaudited condensed consolidated financial statements has been revised for the segment realignment discussed above and the revision to previously issued financial statements discussed in Note 3 to the unaudited condensed consolidated financial statements.