Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

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:

December 31 (in millions)	2023		2022		2021
Cash and cash equivalents	$	1,271.8	$	358.0	$	258.4
Restricted cash		10.5		0.8		0.5
Total cash, cash equivalents and restricted cash    presented in the consolidated statements of cash flows	$	1,282.3	$	358.8	$	258.9

Estimated Service Lives for Property Plant and Equipment

The estimated service lives for property, plant and equipment are as follows:

Class of Assets	Range of Service Lives
Buildings	5 to 30 years
Machinery & Equipment	2 to 20 years
Land Improvements	5 to 60 years

Components of Changes in Accumulated Other Comprehensive Loss and Related Cumulative Noncurrent Deferred Tax Assets

The components of the changes in accumulated other comprehensive loss and related cumulative noncurrent deferred tax assets are as follows:

years ended December 31	Pension and Postretirement Benefit Plans			Foreign Currency			Total
(in millions)	2023
Accumulated other comprehensive loss at beginning of period	$	(36.5	)	$	(2.0	)	$	(38.5	)
Other comprehensive (loss) earnings before    reclassifications, net of tax		(15.7	)		0.8			(14.9	)
Amounts reclassified from accumulated other    comprehensive loss, net of tax		4.2			—			4.2
Other comprehensive (loss) earnings, net of tax		(11.5	)		0.8			(10.7	)
Accumulated other comprehensive loss at end of period	$	(48.0	)	$	(1.2	)	$	(49.2	)
Cumulative noncurrent deferred tax assets at end of period	$	53.8		$	—		$	53.8
	2022
Accumulated other comprehensive loss at beginning of period	$	(97.6	)	$	—		$	(97.6	)
Other comprehensive earnings (loss) before    reclassifications, net of tax		51.6			(2.0	)		49.6
Amounts reclassified from accumulated other    comprehensive loss, net of tax		9.5			—			9.5
Other comprehensive earnings (loss), net of tax		61.1			(2.0	)		59.1
Accumulated other comprehensive loss at end of period	$	(36.5	)	$	(2.0	)	$	(38.5	)
Cumulative noncurrent deferred tax assets at end of period	$	50.1		$	—		$	50.1
	2021
Accumulated other comprehensive loss at beginning of period	$	(158.1	)	$	(0.3	)	$	(158.4	)
Other comprehensive earnings before reclassifications,    net of tax		51.3			0.3			51.6
Amounts reclassified from accumulated other    comprehensive loss, net of tax		9.2			—			9.2
Other comprehensive earnings, net of tax		60.5			0.3			60.8
Accumulated other comprehensive loss at end of period	$	(97.6	)	$	—		$	(97.6	)
Cumulative noncurrent deferred tax assets at end of period	$	69.7		$	—		$	69.7

Reclassification Out of Accumulated Other Comprehensive Loss

Reclassifications out of accumulated other comprehensive loss are as follows:

years ended December 31 (in millions)	2023			2022			2021			Affected line items in the consolidated statements of earnings
Pension and postretirement benefit plans:
Settlement charge	$	—		$	4.6		$	—
Amortization of:
Prior service cost		5.6			4.0			—
Actuarial loss		—			3.7			12.1
		5.6			12.3			12.1		Other nonoperating income, net
Tax effect		(1.4	)		(2.8	)		(2.9	)	Income tax expense
Total	$	4.2		$	9.5		$	9.2

Basic and Diluted Earnings from Continuing Operations Per Common Share

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

years ended December 31 (in millions)	2023		2022		2021
Net earnings from continuing operations attributable to    Martin Marietta	$	1,199.8	$	856.3	$	702.0
Less: distributed and undistributed earnings attributable to    unvested participating securities		—		—		0.2
Basic and diluted net earnings from continuing operations    attributable to common shareholders attributable to Martin    Marietta	$	1,199.8	$	856.3	$	701.8
Basic weighted-average common shares outstanding		61.9		62.3		62.4
Effect of dilutive employee and director awards		0.2		0.2		0.2
Diluted weighted-average common shares outstanding		62.1		62.5		62.6