Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2023

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:

	September 30,		December 31,
	2023		2022
	(Dollars in Millions)
Cash and cash equivalents	$	647.6	$	358.0
Restricted cash		—		0.8
Total cash, cash equivalents and restricted cash    presented in the consolidated statements of cash flows	$	647.6	$	358.8

Consolidated Comprehensive Earnings (Loss)

Consolidated comprehensive earnings (loss) attributable to Martin Marietta is as follows:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2023		2022		2023		2022
	(Dollars in Millions)
Net earnings attributable to Martin Marietta	$	416.7	$	295.3	$	886.4	$	683.2
Other comprehensive earnings (loss), net of tax		0.4		3.0		3.2		(27.5	)
Consolidated comprehensive earnings    attributable to Martin Marietta	$	417.1	$	298.3	$	889.6	$	655.7

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 September 30, 2023
Balance at beginning of period	$	(34.3	)	$	(1.4	)	$	(35.7	)
Other comprehensive loss before reclassifications,    net of tax		—			(0.7	)		(0.7	)
Amounts reclassified from accumulated other    comprehensive loss, net of tax		1.1			—			1.1
Other comprehensive earnings (loss), net of tax		1.1			(0.7	)		0.4
Balance at end of period	$	(33.2	)	$	(2.1	)	$	(35.3	)
	Three Months Ended September 30, 2022
Balance at beginning of period	$	(127.6	)	$	(0.5	)	$	(128.1	)
Other comprehensive loss before reclassifications,    net of tax		—			(1.9	)		(1.9	)
Amounts reclassified from accumulated other    comprehensive loss, net of tax		4.9			—			4.9
Other comprehensive earnings (loss), net of tax		4.9			(1.9	)		3.0
Balance at end of period	$	(122.7	)	$	(2.4	)	$	(125.1	)

	(Dollars in Millions)
	Pension and Postretirement Benefit Plans			Foreign Currency			Accumulated Other Comprehensive Loss
	Nine Months Ended September 30, 2023
Balance at beginning of period	$	(36.5	)	$	(2.0	)	$	(38.5	)
Other comprehensive earnings (loss) before reclassifications,    net of tax		0.2			(0.1	)		0.1
Amounts reclassified from accumulated other    comprehensive loss, net of tax		3.1			—			3.1
Other comprehensive earnings (loss), net of tax		3.3			(0.1	)		3.2
Balance at end of period	$	(33.2	)	$	(2.1	)	$	(35.3	)
	Nine Months Ended September 30, 2022
Balance at beginning of period	$	(97.6	)	$	—		$	(97.6	)
Other comprehensive loss before reclassifications,    net of tax		(33.0	)		(2.4	)		(35.4	)
Amounts reclassified from accumulated other    comprehensive loss, net of tax		7.9			—			7.9
Other comprehensive loss, net of tax		(25.1	)		(2.4	)		(27.5	)
Balance at end of period	$	(122.7	)	$	(2.4	)	$	(125.1	)

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						Nine Months Ended
	September 30,						September 30,
	2023			2022			2023			2022
	(Dollars in Millions)
Balance at beginning of period	$	49.4		$	79.5		$	50.1		$	69.7
Tax effect of other comprehensive    (earnings) loss		(0.4	)		(1.6	)		(1.1	)		8.2
Balance at end of period	$	49.0		$	77.9		$	49.0		$	77.9

Reclassification Out of Accumulated Other Comprehensive Loss

Reclassifications out of accumulated other comprehensive loss are as follows:

	Three Months Ended						Nine Months Ended						Affected line items in the consolidated
	September 30,						September 30,						statements of earnings
	2023			2022			2023			2022			and comprehensive earnings
	(Dollars in Millions)
Pension and postretirement    benefit plans
Settlement charge	$	—		$	4.5		$	—		$	4.5
Amortization of:
Prior service cost		1.4			1.1			4.2			3.2
Actuarial loss		0.1			0.9			—			2.8
		1.5			6.5			4.2			10.5		Other nonoperating income, net
Tax effect		(0.4	)		(1.6	)		(1.1	)		(2.6	)	Income tax expense
Total	$	1.1		$	4.9		$	3.1		$	7.9

Basic and Diluted Earnings from Continuing Operations Per Common Share

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

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2023		2022		2023		2022
	(In Millions)
Basic weighted-average common shares outstanding		61.8		62.3		61.9		62.4
Effect of dilutive employee and director awards		0.2		0.2		0.2		0.1
Diluted weighted-average common shares outstanding		62.0		62.5		62.1		62.5