Description of Business	3 Months Ended
Mar. 28, 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 reorganized its business segments to better align its organizational structure with customer priorities and increase operational efficiencies. After the realignment, L-3’s structure consists of the following four segments: Aerospace Systems, Electronic Systems, Communication Systems and National Security Solutions, as further described below. Aerospace Systems: combines the operations of the former Platform & Logistics Solutions (P&LS) segment with Intelligence, Surveillance and Reconnaissance (ISR) Systems. ISR Systems was part of the former Command, Control, Communications, Intelligence, Surveillance and Reconnaissance (C³ISR) segment. Aerospace Systems delivers integrated solutions for the global ISR market and provides modernization, upgrade, sustainment, and maintenance and logistics support for a wide variety of aircraft and ground systems. Electronic Systems: includes all of its previous businesses historically included in this segment except the Microwave Products businesses, which are now part of Communication Systems. Electronic Systems provides a broad range of components, products, subsystems, systems and related services for military and commercial customers. Communication Systems: combines the operations of the Microwave Products businesses, which were previously part of the Electronic Systems reportable segment, with the operations of the Networked and Secure Communications Products businesses, previously part of the former C³ISR segment. Communication Systems delivers products and services for the global communications market, specializing in strategic and tactical airborne, space, ground and sea-based communication systems. National Security Solutions (NSS): remains unchanged. NSS will continue to provide cybersecurity solutions, high-performance computing, enterprise information technology (IT) services, analytics and intelligence analysis. Financial information with respect to the Company’s segments is included in Note 22 to the unaudited condensed consolidated financial statements. Financial information for the first quarter of 2013 in these unaudited condensed consolidated financial statements has been revised for the segment realignment discussed above.

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 reorganized its business segments to better align its organizational structure with customer priorities and increase operational efficiencies. After the realignment, L-3’s structure consists of the following four segments: Aerospace Systems, Electronic Systems, Communication Systems and National Security Solutions, as further described below.

Aerospace Systems: combines the operations of the former Platform & Logistics Solutions (P&LS) segment with Intelligence, Surveillance and Reconnaissance (ISR) Systems. ISR Systems was part of the former Command, Control, Communications, Intelligence, Surveillance and Reconnaissance (C³ISR) segment. Aerospace Systems delivers integrated solutions for the global ISR market and provides modernization, upgrade, sustainment, and maintenance and logistics support for a wide variety of aircraft and ground systems.

Electronic Systems: includes all of its previous businesses historically included in this segment except the Microwave Products businesses, which are now part of Communication Systems. Electronic Systems provides a broad range of components, products, subsystems, systems and related services for military and commercial customers.

Communication Systems: combines the operations of the Microwave Products businesses, which were previously part of the Electronic Systems reportable segment, with the operations of the Networked and Secure Communications Products businesses, previously part of the former C³ISR segment. Communication Systems delivers products and services for the global communications market, specializing in strategic and tactical airborne, space, ground and sea-based communication systems.

National Security Solutions (NSS): remains unchanged. NSS will continue to provide cybersecurity solutions, high-performance computing, enterprise information technology (IT) services, analytics and intelligence analysis.

Financial information with respect to the Company’s segments is included in Note 22 to the unaudited condensed consolidated financial statements. Financial information for the first quarter of 2013 in these unaudited condensed consolidated financial statements has been revised for the segment realignment discussed above.