Consolidated Cases Number Of Lawsuits

No definition available.

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

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

Carrying amount as of the balance sheet date, net of allowance for doubtful accounts, of account and note receivables due from other than related parties.

+ References

+ Details

Name:	us-gaap_AccountsAndNotesReceivableNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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=68065756&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 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 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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 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

+ 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

- 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_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_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_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) $ in Millions	1 Months Ended		3 Months Ended	6 Months Ended
	Jun. 30, 2014 plaintiff	May 31, 2014 plaintiff	Apr. 30, 2012 LegalMatter executive	Jul. 01, 2016 USD ($)	Jul. 31, 2013 USD ($)	Nov. 30, 2008 USD ($)
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 Chief Executive Officers \| executive			2
Greek Government Contract
Legal Proceedings [Line Items]
Arbitral award				$ 21	$ 43
Recorded losses				123
Receivable				2
Greek Government Contract \| Invoice for Undisputed Portion of Contract
Legal Proceedings [Line Items]
Contracts receivable						$ 15
Greek Government Contract \| Value Added Taxes
Legal Proceedings [Line Items]
Contracts receivable				28
Greek Government Contract \| Letters of Credit Relating to Delivery
Legal Proceedings [Line Items]
Letter of credit available to the company				16
Greek Government Contract \| Standby Letters of Credit
Legal Proceedings [Line Items]
Letter of credit available to the company				18
Greek Government Contract \| Letters Of Credit Related System Support And Maintenance \| Letters of Credit Relating to Delivery
Legal Proceedings [Line Items]
Amount outstanding				$ 4
Data Privacy Litigation
Legal Proceedings [Line Items]
Number of plaintiffs \| plaintiff	2	2