Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	Apr. 30, 2021
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Trading Symbol	MLM
Entity Registrant Name	MARTIN MARIETTA MATERIALS, INC.
Entity Central Index Key	0000916076
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Title of 12(b) Security	Common Stock (Par Value $0.01)
Security Exchange Name	NYSE
Entity File Number	1-12744
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	NC
Entity Tax Identification Number	56-1848578
Entity Address, Address Line One	4123 Parklake Avenue
Entity Address, City or Town	Raleigh
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27612
City Area Code	919
Local Phone Number	781-4550
Document Quarterly Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		62,368,903
Former Address [Member]
Document Information [Line Items]
Entity Address, Address Line One	2710 Wycliff Road
Entity Address, City or Town	Raleigh
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27607