Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2016	Feb. 17, 2017	Jun. 24, 2016
Document And Entity Information [Abstract]
Entity Registrant Name	L3 TECHNOLOGIES, INC.
Entity Central Index Key	0001039101
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 10.8
Entity Common Stock, Shares Outstanding		77,798,844
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016