Administrative Agreement, Term

No definition available.

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- Definition

Consolidated Cases Number Of Lawsuits

+ References

No definition available.

+ Details

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- Definition

Cumulative losses on a customer contract.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Deferred Prosecution Agreement Provides Monitor Service Period

+ References

No definition available.

+ Details

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- Definition

Legal Proceedings [Line Items]

+ References

No definition available.

+ Details

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- Definition

Loss Contingency Claims Resolved

+ References

No definition available.

+ Details

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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

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- 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=6471494&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

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph c

-Article 5

+ Details

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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

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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 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

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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

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Balance Type:	na
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- 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=31042434&loc=d3e3536-108585

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable for statutory income, sales, use, payroll, excise, real, property and other taxes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.15)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.15)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Subparagraph 1, 5

-Article 9

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Article 7

+ Details

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

- 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

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 02

-Paragraph 8

-Article 5

+ Details

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

- Details

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- Details

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- Details

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- Details

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- Details

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Legal Proceedings - Additional Information (Detail)	1 Months Ended				3 Months Ended	9 Months Ended
Legal Proceedings - Additional Information (Detail)	Jun. 30, 2014 plaintiff	May. 31, 2014 plaintiff	Aug. 31, 2012	Mar. 31, 2012 USD ($)	Apr. 30, 2012 executive LegalMatter	Oct. 02, 2015 USD ($)	Jul. 31, 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 (years)			3 years
Amount outstanding						$ 0
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 Chief Executive Officers \| executive					2
Greek Government Contract
Legal Proceedings [Line Items]
Arbitral award						21,000,000	$ 44,000,000
Recorded losses						123,000,000
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]
Receivables relating to value added taxes						17,000,000
Contracts receivable						28,000,000
Tax withholdings						5,000,000
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						18,000,000
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