Consolidated Statements of Earnings and Comprehensive Earnings (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Total Revenues	$ 1,270.6	$ 1,279.5	$ 2,228.9	$ 2,218.4
Total Cost of Revenues	890.1	922.6	1,706.0	1,718.6
Gross Profit	380.5	356.9	522.9	499.8
Selling, general & administrative expenses	71.2	72.4	149.9	150.7
Acquisition-related expenses	0.5		0.8	0.2
Other operating expenses and (income), net	2.4	(1.4)	8.0	(6.2)
Earnings from Operations	306.4	285.9	364.2	355.1
Interest expense	31.2	33.3	61.0	66.2
Other nonoperating (income) and expenses, net	(3.8)	13.2	(1.9)	11.7
Earnings before income tax expense	279.0	239.4	305.1	277.2
Income tax expense	61.4	49.9	61.6	44.9
Consolidated net earnings	217.6	189.5	243.5	232.3
Net Earnings Attributable to Martin Marietta Materials, Inc.	217.6	189.5	243.5	232.3
Consolidated Comprehensive Earnings:
Earnings attributable to Martin Marietta Materials, Inc.	220.8	192.5	247.1	238.6
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 220.8	$ 192.5	$ 247.1	$ 238.6
Net Earnings Attributable to Martin Marietta Materials, Inc. Per Common Share:
Basic attributable to common shareholders	$ 3.49	$ 3.02	$ 3.91	$ 3.71
Diluted attributable to common shareholders	$ 3.49	$ 3.01	$ 3.90	$ 3.69
Weighted-Average Common Shares Outstanding:
Basic	62.3	62.6	62.3	62.6
Diluted	62.3	62.7	62.4	62.7
Products and Services
Total Revenues	$ 1,189.5	$ 1,196.1	$ 2,080.5	$ 2,074.4
Total Cost of Revenues	807.4	838.3	1,554.8	1,572.5
Freight
Total Revenues	81.1	83.4	148.4	144.0
Total Cost of Revenues	$ 82.7	$ 84.3	$ 151.2	$ 146.1