Description of Business	12 Months Ended
Dec. 31, 2016
Description of Business [Abstract]
Description of Business	1. Description of Business L-3 Communications Holdings, Inc. (L-3 Holdings), a Delaware corporation organized in April 1997, derived all of its operating income and cash flows from its wholly-owned subsidiary, L-3 Communications Corporation (L-3 Corp). On December 31, 2016, the Company completed an internal reorganization to eliminate its holding company structure. Pursuant to the reorganization, L-3 Holdings was merged (the Merger) with and into L-3 Corp, with the subsidiary being the surviving entity in the Merger (the Surviving Entity). Immediately following the completion of the Merger, the name of the Surviving Entity was changed to L3 Technologies, Inc. (the Name Change). As a result of the Merger and the Name Change, all outstanding shares of L-3 Holdings’ common stock were automatically converted into the same number of shares of common stock of L3 Technologies, Inc., with economic, voting and other rights that are substantially identical. The common stock of L3 Technologies, Inc. commenced trading effective January 3, 2017 (the first trading day of 2017) on the New York Stock Exchange under the ticker symbol “LLL”, the same ticker symbol previously used by L-3 Holdings. L3 Technologies, Inc. (L3 Technologies Inc. and, together with its subsidiaries, referred to herein as L3 or the Company), is a prime contractor in Intelligence, Surveillance and Reconnaissance (ISR) systems, aircraft sustainment (including modifications, logistics and maintenance), simulation and training, night vision and image intensification equipment and security and detection systems. L3 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), foreign governments, and domestic and international commercial customers. The Company is the successor of L-3 Communications Holdings, Inc. The Company has the following three reportable segments: (1) Electronic Systems, (2) Aerospace Systems and (3) Communication Systems. Electronic Systems provides a broad range of products and services, including 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, aviation products & security systems, warrior systems and advanced programs. Aerospace Systems delivers integrated solutions for the global ISR market and provides engineering, 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 space, airborne, ground and sea-based communication systems. Effective March 1, 2017, the Company will realign its Electronic Systems segment in connection with the retirement of the segment’s president in the second quarter of 2017. The current Electronic Systems segment will be split into two separate segments named (1) Electronic Systems and (2) Sensor Systems. Accordingly, the Company’s structure will consist of the following four segments: (1) Aerospace Systems, (2) Communication Systems, (3) Electronic Systems and (4) Sensor Systems. The Company will report its results under the realigned business segments commencing in the first quarter of 2017 at which time the Company will restate the corresponding information for prior periods. Financial information with respect to each of its segments is included in Note 21. On December 7, 2015, the Company entered into a definitive agreement to sell its National Security Solutions (NSS) business to CACI International Inc. The transaction was completed on February 1, 2016. NSS provided cybersecurity solutions, high-performance computing, enterprise IT services, analytics and intelligence analysis to the DoD, U.S. Government intelligence agencies, federal civilian agencies and foreign governments. In accordance with Accounting Standards Update (ASU) 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity, the assets and liabilities and results of operations of NSS are reported as discontinued operations for all periods presented. Accordingly, all references made to financial data in this Annual Report on Form 10-K are to the Company’s continuing operations, unless specifically noted. See Note 3 for additional information.

1. Description of Business

L-3 Communications Holdings, Inc. (L-3 Holdings), a Delaware corporation organized in April 1997, derived all of its operating income and cash flows from its wholly-owned subsidiary, L-3 Communications Corporation (L-3 Corp). On December 31, 2016, the Company completed an internal reorganization to eliminate its holding company structure. Pursuant to the reorganization, L-3 Holdings was merged (the Merger) with and into L-3 Corp, with the subsidiary being the surviving entity in the Merger (the Surviving Entity). Immediately following the completion of the Merger, the name of the Surviving Entity was changed to L3 Technologies, Inc. (the Name Change).

As a result of the Merger and the Name Change, all outstanding shares of L-3 Holdings’ common stock were automatically converted into the same number of shares of common stock of L3 Technologies, Inc., with economic, voting and other rights that are substantially identical. The common stock of L3 Technologies, Inc. commenced trading effective January 3, 2017 (the first trading day of 2017) on the New York Stock Exchange under the ticker symbol “LLL”, the same ticker symbol previously used by L-3 Holdings.

L3 Technologies, Inc. (L3 Technologies Inc. and, together with its subsidiaries, referred to herein as L3 or the Company), is a prime contractor in Intelligence, Surveillance and Reconnaissance (ISR) systems, aircraft sustainment (including modifications, logistics and maintenance), simulation and training, night vision and image intensification equipment and security and detection systems. L3 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), foreign governments, and domestic and international commercial customers. The Company is the successor of L-3 Communications Holdings, Inc.

The Company has the following three reportable segments: (1) Electronic Systems, (2) Aerospace Systems and (3) Communication Systems. Electronic Systems provides a broad range of products and services, including 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, aviation products & security systems, warrior systems and advanced programs. Aerospace Systems delivers integrated solutions for the global ISR market and provides engineering, 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 space, airborne, ground and sea-based communication systems. Effective March 1, 2017, the Company will realign its Electronic Systems segment in connection with the retirement of the segment’s president in the second quarter of 2017. The current Electronic Systems segment will be split into two separate segments named (1) Electronic Systems and (2) Sensor Systems. Accordingly, the Company’s structure will consist of the following four segments: (1) Aerospace Systems, (2) Communication Systems, (3) Electronic Systems and (4) Sensor Systems. The Company will report its results under the realigned business segments commencing in the first quarter of 2017 at which time the Company will restate the corresponding information for prior periods. Financial information with respect to each of its segments is included in Note 21.

On December 7, 2015, the Company entered into a definitive agreement to sell its National Security Solutions (NSS) business to CACI International Inc. The transaction was completed on February 1, 2016. NSS provided cybersecurity solutions, high-performance computing, enterprise IT services, analytics and intelligence analysis to the DoD, U.S. Government intelligence agencies, federal civilian agencies and foreign governments. In accordance with Accounting Standards Update (ASU) 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity, the assets and liabilities and results of operations of NSS are reported as discontinued operations for all periods presented. Accordingly, all references made to financial data in this Annual Report on Form 10-K are to the Company’s continuing operations, unless specifically noted. See Note 3 for additional information.