Consolidated Statements of Comprehensive Earnings - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Consolidated net earnings	$ 1,169.4	$ 866.8	$ 702.8
Defined benefit pension and postretirement plans:
Net (loss) gain arising during period, net of tax of $(5.1), $28.6 and $16.8, respectively	(15.7)	87.9	51.3
Prior service cost arising during period, net of tax of $0.0, $(11.8) and $0.0, respectively		(36.3)
Amortization of prior service cost, net of tax of $1.4, $0.9 and $0.0, respectively	4.2	3.1
Amortization of actuarial loss, net of tax of $0.0, $0.8 and $2.9, respectively		2.9	9.2
Amount recognized in net periodic pension cost due to settlement, net of tax of $0.0, $1.1 and $0.0, respectively		3.5
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(11.5)	61.1	60.5
Foreign currency translation gain (loss)	0.8	(2.0)	0.3
Other Comprehensive Income (Loss), Net of Tax	(10.7)	59.1	60.8
Consolidated comprehensive earnings	1,158.7	925.9	763.6
Less: Comprehensive earnings attributable to noncontrolling interests			0.3
Comprehensive Earnings Attributable to Martin Marietta	$ 1,158.7	$ 925.9	$ 763.3