Schedule of Net Periodic Benefit Costs (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
FAS/CAS pension adjustment	$ 471	$ 376	$ (482)

This item represents the difference between pension expense calculated for financial reporting purposes under GAAP and pension costs calculated and funded in accordance with U.S. Government Cost Accounting Standards (CAS).

No definition available.

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