Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2025

Significant Accounting Policies [Line Items]

Reconciliation of Cash, Cash Equivalents and Restricted Cash

The following table reconciles cash, cash equivalents and restricted cash as reported on the consolidated balance sheets to the aggregated amounts presented on the consolidated statements of cash flows:

	June 30,		December 31,
	2025		2024
	(Dollars in Millions)
Cash and cash equivalents	$	225	$	670
Restricted cash		11		—
Total cash, cash equivalents and restricted cash    presented in the consolidated statements of cash flows	$	236	$	670

Consolidated Comprehensive Earnings

Consolidated comprehensive earnings attributable to Martin Marietta are as follows:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2025		2024		2025		2024
	(Dollars in Millions)
Net earnings attributable to Martin Marietta	$	328	$	294	$	444	$	1,339
Other comprehensive earnings, net of tax		3		1		4		1
Consolidated comprehensive earnings    attributable to Martin Marietta	$	331	$	295	$	448	$	1,340

Changes in Accumulated Other Comprehensive Loss Net of Tax

The components of the changes in accumulated other comprehensive loss, net of tax, are as follows:

	(Dollars in Millions)
	Pension and Postretirement Benefit Plans			Foreign Currency			Accumulated Other Comprehensive Loss
	Three Months Ended June 30, 2025
Balance at beginning of period	$	(8	)	$	(4	)	$	(12	)
Other comprehensive earnings before reclassifications,    net of tax		—			2			2
Amounts reclassified from accumulated other    comprehensive loss, net of tax		1			—			1
Other comprehensive earnings, net of tax		1			2			3
Balance at end of period	$	(7	)	$	(2	)	$	(9	)
	Three Months Ended June 30, 2024
Balance at beginning of period	$	(47	)	$	(2	)	$	(49	)
Amounts reclassified from accumulated other    comprehensive loss, net of tax		1			—			1
Other comprehensive earnings, net of tax		1			—			1
Balance at end of period	$	(46	)	$	(2	)	$	(48	)

	(Dollars in Millions)
	Pension and Postretirement Benefit Plans			Foreign Currency			Accumulated Other Comprehensive Loss
	Six Months Ended June 30, 2025
Balance at beginning of period	$	(9	)	$	(4	)	$	(13	)
Other comprehensive earnings before reclassifications,    net of tax		—			2			2
Amounts reclassified from accumulated other    comprehensive loss, net of tax		2			—			2
Other comprehensive earnings, net of tax		2			2			4
Balance at end of period	$	(7	)	$	(2	)	$	(9	)
	Six Months Ended June 30, 2024
Balance at beginning of period	$	(48	)	$	(1	)	$	(49	)
Other comprehensive loss before reclassifications,    net of tax		—			(1	)		(1	)
Amounts reclassified from accumulated other    comprehensive loss, net of tax		2			—			2
Other comprehensive earnings (loss), net of tax		2			(1	)		1
Balance at end of period	$	(46	)	$	(2	)	$	(48	)

Noncurrent Deferred Tax Assets Recorded in Accumulated Other Comprehensive Loss

Changes in net noncurrent deferred tax assets related to accumulated other comprehensive loss are as follows:

	Pension and Postretirement Benefit Plans
	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2025		2024		2025			2024
	(Dollars in Millions)
Balance at beginning of period	$	40	$	53	$	41		$	54
Tax effect of other comprehensive    earnings		—		—		(1	)		(1	)
Balance at end of period	$	40	$	53	$	40		$	53

Reclassification Out of Accumulated Other Comprehensive Loss

Reclassifications out of accumulated other comprehensive loss are as follows:

	Three Months Ended					Six Months Ended						Affected line items in the consolidated
	June 30,					June 30,						statements of earnings
	2025		2024			2025			2024			and comprehensive earnings
	(Dollars in Millions)
Pension and postretirement    benefit plans
Amortization of prior service    cost	$	1	$	2		$	3		$	3		Other nonoperating income, net
Tax effect		—		(1	)		(1	)		(1	)	Income tax expense
Total	$	1	$	1		$	2		$	2

Basic and Diluted Earnings from Continuing Operations Per Common Share

The following table reconciles the denominator for basic and diluted earnings per common share:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2025		2024		2025		2024
	(In Millions)
Basic weighted-average common shares outstanding		60.3		61.5		60.6		61.6
Effect of dilutive employee and director awards		0.1		0.1		0.1		0.2
Diluted weighted-average common shares outstanding		60.4		61.6		60.7		61.8