Related Party Transactions (Additional Information) (Detail) (USD $)	9 Months Ended						0 Months Ended
	Oct. 31, 2014	Oct. 31, 2014 Leidos Holdings Inc,	Oct. 31, 2014 Notes Which Mature In December 2020	Oct. 31, 2014 Notes Which Mature In December 2040	Oct. 31, 2014 Notes Which Mature In July 2033	Oct. 31, 2014 Notes Which Mature In July 2032	Sep. 26, 2013 SAIC Leidos Holdings Inc,
Related Party Transaction [Line Items]
Notes payable			$ 450,000,000	$ 300,000,000	$ 300,000,000	$ 250,000,000
Stated interest rate			4.45%	5.95%	5.50%	7.13%
Credit facility, maturity date	2018
Notes receivable		1,400,000,000
Distribution upon separation							$ 736,000,000