Equity method investment other than temporary impairment earnings per share.

No definition available.

Name:	lmt_EquityMethodInvestmentOtherThanTemporaryImpairmentEarningsPerShare
Namespace Prefix:	lmt_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Equity method investment other than temporary impairment net of tax.

+ References

No definition available.

+ Details

Name:	lmt_EquityMethodInvestmentOtherThanTemporaryImpairmentNetOfTax
Namespace Prefix:	lmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Gain (Loss) on Sale of Properties, After Tax

+ References

No definition available.

+ Details

Name:	lmt_GainLossonSaleofPropertiesAfterTax
Namespace Prefix:	lmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Gain (Loss) on Sale of Properties, After Tax Per Share Amount

+ References

No definition available.

+ Details

Name:	lmt_GainLossonSaleofPropertiesAfterTaxPerShareAmount
Namespace Prefix:	lmt_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Quarterly Financial Information [Line Items]

+ References

No definition available.

+ Details

Name:	lmt_QuarterlyFinancialInformationLineItems
Namespace Prefix:	lmt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit)

+ References

No definition available.

+ Details

Name:	lmt_TaxCutsandJobsActof2017IncompleteAccountingProvisionalIncomeTaxExpenseBenefit
Namespace Prefix:	lmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit), Effect On Earnings Per Share

+ References

No definition available.

+ Details

Name:	lmt_TaxCutsandJobsActof2017IncompleteAccountingProvisionalIncomeTaxExpenseBenefitEffectOnEarningsPerShare
Namespace Prefix:	lmt_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Valuation allowances and reserves charged to cost and expense earnings per share.

+ References

No definition available.

+ Details

Name:	lmt_ValuationAllowancesAndReservesChargedToCostAndExpenseEarningsPerShare
Namespace Prefix:	lmt_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Valuation allowances and reserves charged to cost and expense, net of tax.

+ References

No definition available.

+ Details

Name:	lmt_ValuationAllowancesAndReservesChargedToCostAndExpenseNetOfTax
Namespace Prefix:	lmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

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

- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

+ Details

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

- Definition

This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 35
-Paragraph 32
-URI http://asc.fasb.org/extlink&oid=99375318&loc=d3e32787-111569

+ Details

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

- Definition

Gain (loss) from sale or disposal of an organization or integrated set of activities (for example, but not limited to, a partnership or corporation) engaged in providing a product or service in a commercial, industrial, or professional environment.

+ References

No definition available.

+ Details

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

- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

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

- Definition

Amount of increase in the allowances and reserves, which consist of the valuation and qualifying accounts that are either netted against the cost of an asset or that reflect a liability established to represent expected future costs, from charges to costs and expenses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=lmt_AweManagementLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_LandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Summary of Quarterly Information (Unaudited) - Additional Information Narrative (Detail) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended				12 Months Ended
	Aug. 16, 2016	Dec. 31, 2017	Mar. 26, 2017	Dec. 31, 2016	Sep. 25, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information [Line Items]
Additional charge for performance matter on EADGE-T, gross			$ 120
Additional charge for performance matter on EADGE-T, after tax			$ 74
Additional charge for performance matter on EADGE-T, after tax (in dollars per share)			$ 0.25
Equity method investee impairment								$ 90
Remeasurement of deferred tax asset		$ 1,900
Effect of tax cut on earnings per share (in usd per share)		$ 6.80				$ 6.69
Gain on property sale						$ 198	$ 0	0
Net gain on divestiture of business segment						73	1,242	$ 0
AWE Management Limited
Quarterly Financial Information [Line Items]
Net sales				$ 307	$ 103
Net earnings (loss)				$ 3	104
Information Systems & Global Solutions
Quarterly Financial Information [Line Items]
Net gain on divestiture of business segment	$ 1,300	$ 73			$ 1,200		$ 1,200
Land
Quarterly Financial Information [Line Items]
Gain on property sale						198
Gain on property sale, after tax						$ 122
Gain on property sale per share, after tax (in dollars per share)		$ 0.43				$ 0.42
AMMROC
Quarterly Financial Information [Line Items]
Equity method investee impairment			$ 64			$ 64
Increase in net earnings due to profit rate adjustments			$ 40
Increase in diluted earnings per common share due to profit rate adjustments (in dollars per share)			$ 0.14