Related Party Transactions - Additional Information (Detail) (USD $)	12 Months Ended											1 Months Ended
	Jan. 31, 2014	Jan. 31, 2014 Notes Which Mature In December 2020	Jan. 31, 2014 Notes Which Mature In December 2040	Jan. 31, 2014 Notes Which Mature In July 2033	Jan. 31, 2014 Notes Which Mature In July 2032	Jan. 31, 2014 Leidos Holding Inc.	Jan. 31, 2014 Leidos, Inc.	Jan. 31, 2014 Leidos, Inc. Notes Which Mature In December 2020	Jan. 31, 2014 Leidos, Inc. Notes Which Mature In December 2040	Jan. 31, 2014 Leidos, Inc. Notes Which Mature In July 2033	Jan. 31, 2014 Leidos, Inc. Notes Which Mature In July 2032	Jan. 31, 2014 SAIC Leidos, Inc.	Jun. 27, 2013 Pre Spin-off SAIC
Related Party Transaction [Line Items]
Notes payable, related parties								$ 450,000,000	$ 300,000,000	$ 300,000,000	$ 250,000,000
Stated interest rate		4.45%	5.95%	5.50%	7.13%			4.45%	5.95%	5.50%	7.13%
Credit agreement guaranteed by the company prior to spin-off													700,000,000
Credit facility, maturity date							2018
Period extension for portions of intercompany loans (years)	1 year
Note receivable from Leidos Holdings, Inc. (Note 8)						1,100,000,000
Notes payable						22,000,000
Distribution upon separation												736,000,000
Payment towards dividends	$ 356,000,000											$ 356,000,000