Administrative Agreement, Term

No definition available.

Name:	ldos_AdministrativeAgreementTerm
Namespace Prefix:	ldos_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Consolidated Cases Number Of Lawsuits

+ References

No definition available.

+ Details

Name:	ldos_ConsolidatedCasesNumberOfLawsuits
Namespace Prefix:	ldos_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration

- Definition

Cumulative losses on a customer contract.

+ References

No definition available.

+ Details

Name:	ldos_CumulativeContractLosses
Namespace Prefix:	ldos_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Deferred Prosecution Agreement Provides Monitor Service Period

+ References

No definition available.

+ Details

Name:	ldos_DeferredProsecutionAgreementProvidesMonitorServicePeriod
Namespace Prefix:	ldos_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Legal Proceedings [Line Items]

+ References

No definition available.

+ Details

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

- Definition

Loss Contingency Claims Resolved

+ References

No definition available.

+ Details

Name:	ldos_LossContingencyClaimsResolved
Namespace Prefix:	ldos_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Lawsuits

+ References

No definition available.

+ Details

Name:	ldos_NumberOfLawsuits
Namespace Prefix:	ldos_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Former Chief Executive Officers

+ References

No definition available.

+ Details

Name:	ldos_NumberofFormerChiefExecutiveOfficers
Namespace Prefix:	ldos_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Third Party Credit Enhancement, Amount

+ References

No definition available.

+ Details

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

- Definition

Amount billed to customers under long-term contracts or programs but not paid. Excludes amounts due that have been withheld because of retainage provisions in a contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 910
-SubTopic 310
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=51673017&loc=d3e49354-109356

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3(c))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AccountsReceivableBilledForLongTermContractsOrPrograms
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount or range of possible amounts of gain that could be realized upon the resolution of a contingency.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6397426&loc=d3e17499-108355

+ Details

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

- Definition

The amount of the additional liability or refund received or expected based on a final settlement with a taxing authority.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

+ Details

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

- Definition

Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 5
-Subparagraph c
-Article 7

+ Details

Name:	us-gaap_IncomeTaxReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

+ Details

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

- Definition

Number of plaintiffs that have filed claims pertaining to a loss contingency.

+ References

No definition available.

+ Details

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

- Definition

The amount of cash paid for the settlement of litigation or for other legal issues during the 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 (g)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585

+ Details

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

- Definition

Carrying amount as of the balance sheet date of value added taxes due either from customers arising from sales on credit terms, or as previously overpaid to tax authorities.

+ References

+ Details

Name:	us-gaap_ValueAddedTaxReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

- Details

Name:	ldos_LegalProceedingsAndRelatedMattersAxis=ldos_SecuritiesClassActionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ldos_ContractsByThirdPartyAxis=ldos_GreekGovernmentContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_LitigationCaseAxis=ldos_DataPrivacyLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Legal Proceedings - Additional Information (Detail)	1 Months Ended				3 Months Ended	11 Months Ended	14 Months Ended
Legal Proceedings - Additional Information (Detail)	Jun. 30, 2014 plaintiff	May. 30, 2014 plaintiff	Aug. 31, 2012	Mar. 31, 2012 USD ($)	Apr. 30, 2012 LegalMatter	Jan. 01, 2016 USD ($)	Mar. 29, 2013 LegalMatter executive	Jan. 30, 2015 USD ($)	Sep. 27, 2013 USD ($)	Jul. 13, 2013 USD ($)	Nov. 30, 2008 USD ($)
Legal Proceedings [Line Items]
Administrative agreement, term (in years)			5 years
DPA provides that the monitor will serve for a period (in years)			3 years
Amount outstanding						$ 0		$ 0	$ 500,000,000
Timekeeping Contract with City of New York
Legal Proceedings [Line Items]
Cash settlement payment				$ 500,000,000
Securities Class Actions
Legal Proceedings [Line Items]
Number of lawsuits \| LegalMatter					3
Number of lawsuits, withdrawn \| LegalMatter							1
Number of lawsuits, consolidated \| LegalMatter							2
Number of former CEO's \| executive							2
Greek Government Contract
Legal Proceedings [Line Items]
Arbitral award						21,000,000				$ 42,000,000
Recorded losses						123,000,000
Greek Government Contract \| Letters of Credit Relating to Delivery
Legal Proceedings [Line Items]
Letter of credit available to the company						16,000,000
Greek Government Contract \| Standby Letters of Credit
Legal Proceedings [Line Items]
Letter of credit available to the company						17,000,000
Greek Government Contract \| Invoice For Undisputed Portion Of Contract
Legal Proceedings [Line Items]
Contracts receivable											$ 15,000,000
Greek Government Contract \| Value Added Taxes
Legal Proceedings [Line Items]
Contracts receivable						27,000,000
Income Taxes Receivable						5,000,000
Tax refund receivable						3,000,000
Receivables relating to value added taxes						13,000,000
Greek Government Contract \| Letters of Credit Related System Support and Maintenance \| Letters of Credit Relating to Delivery
Legal Proceedings [Line Items]
Amount outstanding						$ 4,000,000
Data Privacy Litigation
Legal Proceedings [Line Items]
Number of plaintiffs \| plaintiff	2	2