Summary of Significant Accounting Policies (Additional Information) (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 30, 2015	Oct. 02, 2015	Oct. 31, 2014	Oct. 02, 2015	Oct. 31, 2014
Significant Accounting Policies [Line Items]
Revenues	$ 373,000,000	$ 1,302,000,000	$ 1,276,000,000	$ 3,805,000,000	$ 3,894,000,000
Net income (loss)	(23,000,000)	94,000,000	72,000,000	196,000,000	(251,000,000)
Total adjustment to cash flow	16,000,000			(176,000,000)	12,000,000
Cash flow from operating activities	11,000,000			378,000,000	294,000,000
Financing activities	47,000,000			229,000,000	382,000,000
Cash flow from discontinued operations	$ 20,000,000			19,000,000	22,000,000
Increase (decrease) in income due to contract estimates		$ 10,000,000	$ 6,000,000	$ 20,000,000	$ 24,000,000
Increase (decrease) in income due to contract estimates per diluted share		$ 0.08	$ 0.05	$ 0.16	$ 0.20
Leidos, Inc.
Significant Accounting Policies [Line Items]
Ownership interest		100.00%		100.00%
Revenues		$ 1,302,000,000	$ 1,276,000,000	$ 3,805,000,000	$ 3,894,000,000
Net income (loss)		94,000,000	$ 72,000,000	196,000,000	(251,000,000)
Total adjustment to cash flow				(176,000,000)	12,000,000
Cash flow from operating activities				378,000,000	294,000,000
Financing activities				49,000,000	104,000,000
Cash flow from discontinued operations				19,000,000	22,000,000
Facility Closing
Significant Accounting Policies [Line Items]
Restructuring charges, net				2,000,000	$ 1,000,000
Notes payable and long-term debt, net of current portion | Notes Which Mature In December 2020 | Designated as Hedging Instrument | Interest rate swaps
Significant Accounting Policies [Line Items]
Hedged instrument, face amount		$ 450,000,000		$ 450,000,000
Stated interest rate		4.45%		4.45%