Document and Entity Information	9 Months Ended
	Oct. 31, 2014	Nov. 24, 2014
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Oct. 31, 2014
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q3
Trading Symbol	LDOS
Entity Registrant Name	Leidos Holdings, Inc.
Entity Central Index Key	0001336920
Current Fiscal Year End Date	--01-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		74,066,871
Leidos, Inc.
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Oct. 31, 2014
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q3
Entity Registrant Name	Leidos, Inc.
Entity Central Index Key	0000353394
Current Fiscal Year End Date	--01-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		5,000