BUSINESS COMBINATIONS, DIVESTITURES, DISCONTINUED OPERATIONS AND ASSETS AND LIABILITIES HELD FOR SALE - Summary of Unaudited Pro Forma Financial Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Business Combination [Abstract]
Revenues	$ 1,947	$ 1,732	$ 3,359	$ 2,966
Net earnings from continuing operations attributable to Martin Marietta	$ 291	$ 315	$ 398	$ 362

Amount of pro forma revenue of combined entity as if acquisition date of business combination occurred as of beginning of period.

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