| Document and Entity Information Document | Jan. 28, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Jan. 28, 2021 |
| Entity Registrant Name | LOCKHEED MARTIN CORPORATION |
| Entity Central Index Key | 0000936468 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 1-11437 |
| Entity Tax Identification Number | 52-1893632 |
| Entity Address, Address Line One | 6801 Rockledge Drive |
| Entity Address, City or Town | Bethesda, |
| Entity Address, State or Province | MD |
| Entity Address, Postal Zip Code | 20817 |
| City Area Code | 301 |
| Local Phone Number | 897-6000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $1 par value |
| Trading Symbol | LMT |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
