Accumulated Other Comprehensive Loss (Schedule of Accumulated Other Comprehensive Loss) (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Oct. 31, 2014	Jan. 31, 2014
Equity [Abstract]
Foreign currency translation adjustments, tax effect	$ (1)	$ (1)
Unrecognized net loss on settled derivative instruments associated with outstanding debt, tax effect	3	3
Unrecognized net loss on defined benefit plan, taxes	2	2
Total accumulated other comprehensive loss, tax effect	$ 4	$ 4

The tax effect from accumulated adjustment, that results from the process of translating subsidiary financial statements and foreign equity investments into the reporting currency from the functional currency of the reporting entity, net of reclassification of realized foreign currency translation gains (losses).

No definition available.

Name:	ldos_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax
Namespace Prefix:	ldos_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant