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Significant Accounting Policies (Tables) | 9 Months Ended
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Sep. 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:
|  | September 30, |  |  | December 31, |
|  | 2025 |  |  | 2024 |
|  | (Dollars in Millions) |
Cash and cash equivalents |  | $ | 57 |  |  | $ | 670 |
Restricted cash |  |  | 13 |  |  |  | — |
Total cash, cash equivalents and restricted cash presented in the consolidated statements of cash flows |  | $ | 70 |  |  | $ | 670 |
Consolidated Comprehensive Earnings | Consolidated comprehensive earnings attributable to Martin Marietta are as follows:
|  | Three Months Ended |  |  | Nine Months Ended |
|  | September 30, |  |  | September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
|  | (Dollars in Millions) |
Net earnings attributable to Martin Marietta |  | $ | 414 |  |  | $ | 363 |  |  | $ | 858 |  |  | $ | 1,701 |
Other comprehensive earnings, net of tax |  |  | 4 |  |  |  | 2 |  |  |  | 8 |  |  |  | 3 |
Consolidated comprehensive earnings attributable to Martin Marietta |  | $ | 418 |  |  | $ | 365 |  |  | $ | 866 |  |  | $ | 1,704 |
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, 2025 |
Balance at beginning of period |  | $ | (7 | ) |  | $ | (2 | ) |  | $ | (9 | )
Other comprehensive loss before reclassifications, net of tax |  |  | — |  |  |  | (1 | ) |  |  | (1 | )
Amounts reclassified from accumulated other comprehensive loss, net of tax |  |  | 5 |  |  |  | — |  |  |  | 5 |
Other comprehensive earnings (loss), net of tax |  |  | 5 |  |  |  | (1 | ) |  |  | 4 |
Balance at end of period |  | $ | (2 | ) |  | $ | (3 | ) |  | $ | (5 | )
|  | Three Months Ended September 30, 2024 |
Balance at beginning of period |  | $ | (46 | ) |  | $ | (2 | ) |  | $ | (48 | )
Amounts reclassified from accumulated other comprehensive loss, net of tax |  |  | 2 |  |  |  | — |  |  |  | 2 |
Other comprehensive earnings, net of tax |  |  | 2 |  |  |  | — |  |  |  | 2 |
Balance at end of period |  | $ | (44 | ) |  | $ | (2 | ) |  | $ | (46 | )
|  | (Dollars in Millions) |
|  | Pension and Postretirement Benefit Plans |  |  | Foreign Currency |  |  | Accumulated Other Comprehensive Loss |
|  | Nine Months Ended September 30, 2025 |
Balance at beginning of period |  | $ | (9 | ) |  | $ | (4 | ) |  | $ | (13 | )
Other comprehensive earnings before reclassifications, net of tax |  |  | — |  |  |  | 1 |  |  |  | 1 |
Amounts reclassified from accumulated other comprehensive loss, net of tax |  |  | 7 |  |  |  | — |  |  |  | 7 |
Other comprehensive earnings, net of tax |  |  | 7 |  |  |  | 1 |  |  |  | 8 |
Balance at end of period |  | $ | (2 | ) |  | $ | (3 | ) |  | $ | (5 | )
|  | Nine Months Ended September 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 |  |  | 4 |  |  |  | — |  |  |  | 4 |
Other comprehensive earnings (loss), net of tax |  |  | 4 |  |  |  | (1 | ) |  |  | 3 |
Balance at end of period |  | $ | (44 | ) |  | $ | (2 | ) |  | $ | (46 | )
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, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
|  | (Dollars in Millions) |
Balance at beginning of period |  | $ | 40 |  |  | $ | 53 |  |  | $ | 41 |  |  | $ | 54 |
Tax effect of other comprehensive earnings |  |  | (1 | ) |  |  | (1 | ) |  |  | (2 | ) |  |  | (2 | )
Balance at end of period |  | $ | 39 |  |  | $ | 52 |  |  | $ | 39 |  |  | $ | 52 |
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
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |  |  | and comprehensive earnings
|  | (Dollars in Millions) |  |  |
Pension and postretirement benefit plans |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement charge |  | $ | 5 |  |  | $ | — |  |  | $ | 5 |  |  | $ | — |  |  |
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Prior service cost |  |  | 1 |  |  |  | 2 |  |  |  | 4 |  |  |  | 5 |  |  |
Actuarial loss |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 1 |  |  |
|  |  | 6 |  |  |  | 2 |  |  |  | 9 |  |  |  | 6 |  |  | Other nonoperating income, net
Tax effect |  |  | (1 | ) |  |  | — |  |  |  | (2 | ) |  |  | (2 | ) |  | Income tax expense
Total |  | $ | 5 |  |  | $ | 2 |  |  | $ | 7 |  |  | $ | 4 |  |  |
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, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
|  | (In Millions) |
Basic weighted-average common shares outstanding |  |  | 60.3 |  |  |  | 61.1 |  |  |  | 60.5 |  |  |  | 61.5 |
Effect of dilutive employee and director awards |  |  | 0.1 |  |  |  | 0.2 |  |  |  | 0.1 |  |  |  | 0.1 |
Diluted weighted-average common shares outstanding |  |  | 60.4 |  |  |  | 61.3 |  |  |  | 60.6 |  |  |  | 61.6 |

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