Business Segment Information - Additional Information (Detail)	12 Months Ended
Jan. 31, 2014
Segment Reporting [Abstract]
Percentage of revenues contributed by external customers to total revenues	10.00%

Basis For Attributing Revenues From External Customers

No definition available.

Name:	ldos_BasisForAttributingRevenuesFromExternalCustomers
Namespace Prefix:	ldos_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration