Document and Entity Information - shares	6 Months Ended
	Jul. 03, 2015	Jul. 24, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jul. 03, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Trading Symbol	LDOS
Entity Registrant Name	Leidos Holdings, Inc.
Entity Central Index Key	0001336920
Current Fiscal Year End Date	--01-02
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		72,063,425
Leidos, Inc.
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jul. 03, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Entity Registrant Name	Leidos, Inc.
Entity Central Index Key	0000353394
Current Fiscal Year End Date	--01-02
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		5,000