Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	0 Months Ended	1 Months Ended	3 Months Ended	4 Months Ended	12 Months Ended					12 Months Ended							0 Months Ended	12 Months Ended
	Oct. 11, 2013	Jun. 28, 2013	Nov. 01, 2013	Jan. 31, 2014	Jan. 31, 2014 project	Jan. 31, 2013	Jan. 31, 2012	Sep. 27, 2013	Mar. 31, 2013	Jan. 31, 2014 Minimum	Jan. 31, 2014 Maximum	Jan. 31, 2014 Leidos, Inc.	Jan. 31, 2013 Leidos, Inc.	Jan. 31, 2012 Leidos, Inc.	Jan. 31, 2014 One Customer	Jan. 31, 2014 Two Customers	Oct. 11, 2013 Plainfield Renewal Energy Holdings LLC	Jan. 31, 2014 Plainfield Renewal Energy Holdings LLC	Jan. 31, 2014 Other Intangible Assets Minimum	Jan. 31, 2014 Other Intangible Assets Maximum	Jan. 31, 2014 Software and Technology Minimum	Jan. 31, 2014 Software and Technology Maximum	Jan. 31, 2014 Customer Relationships Minimum	Jan. 31, 2014 Customer Relationships Maximum	Jan. 31, 2014 SAIC	Jan. 31, 2013 SAIC	Jan. 31, 2012 SAIC	Sep. 19, 2013 SAIC
Significant Accounting Policies [Line Items]
Ownership interest												100.00%
Ownership in VIE	100.00%
Percentage of shares of newly formed company after spin-off transaction								100.00%
Reverse stock split				0.25
Stock issued to Leidos shareholder upon divestiture of SAIC, ratio																												0.1423
Separation transaction expenses					$ 51																				$ 55	$ 28
Operating cycle (in years)										P1Y
Increase (decrease) in income due to contract estimates					21	19	28
Increase (decrease) in income due to contract estimates per diluted share					$ 0.15	$ 0.12	$ 0.20
Period for billing and collection of unbilled receivables, maximum (in years)					1 year
Period of collection for contract retentions, minimum (in years)					1 year
Payment received from previously deferred payment															25
Bad debt expense			42		44	2	0					44	2	0		41									0	2	1
Number of projects					2
Forgiveness of accounts receivable (net of $32 million bad debt expense)					105	0	0										105	105
Outstanding receivables															39
Cash and cash equivalents original maturity period											3 months
Noncontrolling ownership interest				50.00%	50.00%
Depreciation					45	55	56
Useful life of intangible assets																			2 years	15 years	6 years	15 years	5 years	10 years
Internal research and development costs included in selling, general and administrative expenses					45	47	74
Minimum likelihood of tax benefits being recognized upon ultimate settlement					50.00%
Dividend declared									$ 4.00
Payment towards dividends		$ 342
Period of extension for deferred payment terms (in years)										1 year