Liability For Uncertain Tax Positions

No definition available.

Name:	ldos_LiabilityForUncertainTaxPositions
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Litigation Settlement, Amount, Percentage of Total

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Other Commitments And Contingencies [Line Items]

+ References

No definition available.

+ Details

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- Definition

Surety Bonds, Amount Outstanding

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount recognized for uncertainty in income taxes classified as noncurrent.

+ 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 210.5-02.24)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LiabilityForUncertainTaxPositionsNoncurrent
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 unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=65882285&loc=SL6600010-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Unrecognized Tax Benefit
-URI http://asc.fasb.org/extlink&oid=6527854

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Details

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- Details

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Balance Type:
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- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=ldos_VirnetXIncMember
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- Details

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Other Commitments and Contingencies - Additional Information (Detail) $ in Millions		1 Months Ended
	Feb. 03, 2016 USD ($) patent	Nov. 30, 2012 USD ($) patent	Jul. 01, 2016 USD ($)
Tax Audits And Reviews
Other Commitments And Contingencies [Line Items]
Liabilities for uncertain tax positions			$ 11
Other long-term liabilities			5
Unrecognized tax benefits			7
Standby Letters of Credit
Other Commitments And Contingencies [Line Items]
Amount outstanding			60
Performance Guarantee
Other Commitments And Contingencies [Line Items]
Surety bonds			$ 136
Virnet X Inc
Other Commitments And Contingencies [Line Items]
Patents transferred and awarded	$ 626	$ 368
Number of patents found infringed upon \| patent	4	2
Leidos
Other Commitments And Contingencies [Line Items]
Litigation settlement, percentage of total litigation (in percentage)	25.00%