Litigation Settlement, Amount, Percentage of Total

No definition available.

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

- Definition

Litigation Settlement, Percentage Receivable by the Company

+ References

No definition available.

+ Details

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

- Definition

Number of Patents Infringed

+ References

No definition available.

+ Details

Name:	ldos_NumberOfPatentsInfringed
Namespace Prefix:	ldos_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Other Commitments And Contingencies [Line Items]

+ References

No definition available.

+ Details

Name:	ldos_OtherCommitmentsAndContingenciesLineItems
Namespace Prefix:	ldos_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Surety Bonds, Amount Outstanding

+ References

No definition available.

+ Details

Name:	ldos_SuretyBondsAmountOutstanding
Namespace Prefix:	ldos_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of entity's patents that another entity was found to have infringed.

+ References

No definition available.

+ Details

Name:	us-gaap_GainContingencyPatentsFoundInfringedUponNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a),(b),(c)
-URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437

+ Details

Name:	us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of judgment or settlement awarded to (against) the entity in respect of litigation.

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

+ Details

Name:	us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount charged against operating income increasing loss contingency liability, after adjustments to reduce previously estimated charges.

+ References

+ Details

Name:	us-gaap_LossContingencyAccrualProvision
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Cash received for the settlement of litigation during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585

+ Details

Name:	us-gaap_ProceedsFromLegalSettlements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=ldos_GovernmentInvestigationsAndReviewsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_StandbyLettersOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_PerformanceGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ldos_BechtelSaicCompanyLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=ldos_SAICMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=ldos_VirnetXIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=ldos_LeidosMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Other Commitments and Contingencies - Additional Information (Detail) $ in Millions			1 Months Ended	8 Months Ended	11 Months Ended
	Feb. 03, 2016 USD ($) patent	Dec. 17, 2014 USD ($)	Nov. 30, 2012 USD ($) patent	Sep. 27, 2013 USD ($)	Jan. 01, 2016 USD ($)	Jan. 30, 2015 USD ($)
Other Commitments And Contingencies [Line Items]
Estimated accruals for claims incurred but not yet reported					$ 16	$ 16
Government Investigations And Reviews
Other Commitments And Contingencies [Line Items]
Liability for estimate of loss				$ 27
Loss contingency accrual					43
Standby Letters of Credit
Other Commitments And Contingencies [Line Items]
Amount outstanding					65
Performance Guarantee
Other Commitments And Contingencies [Line Items]
Surety bonds					$ 205
Bechtel SAIC Company, LLC
Other Commitments And Contingencies [Line Items]
Ownership interest (in percentage)					30.00%
SAIC \| Government Investigations And Reviews
Other Commitments And Contingencies [Line Items]
Liability for estimate of loss				18
Virnet X Inc
Other Commitments And Contingencies [Line Items]
Number of patents infringed \| patent			2
Litigation settlement		$ 23	$ 368
Percentage receivable by the company		35.00%
Proceeds from Legal Settlements					$ 11
Pre-Separation \| Government Investigations And Reviews
Other Commitments And Contingencies [Line Items]
Liability for estimate of loss				$ 45
Subsequent Event \| Virnet X Inc
Other Commitments And Contingencies [Line Items]
Litigation settlement	$ 626
Patents found infringed upon, number \| patent	4
Subsequent Event \| Leidos
Other Commitments And Contingencies [Line Items]
Percentage of settlement	25.00%