Segments - Financial Data for Continuing Operations for Company's Reportable Business Segments (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Assets employed	$ 17,724		$ 18,170
Total property additions, including the impact of acquisitions	136	$ 578
Property additions through acquisitions	0	471
Reportable Segments
Segment Reporting Information [Line Items]
Assets employed	16,789		16,662
Total property additions, including the impact of acquisitions	132	575
Property additions through acquisitions	0	471
Operating Segments | East Group
Segment Reporting Information [Line Items]
Assets employed	8,593		8,452
Total property additions, including the impact of acquisitions	67	47
Property additions through acquisitions	0	0
Operating Segments | West Group
Segment Reporting Information [Line Items]
Assets employed	7,913		7,941
Total property additions, including the impact of acquisitions	62	523
Property additions through acquisitions	0	471
Operating Segments | Magnesia Specialties
Segment Reporting Information [Line Items]
Assets employed	283		269
Total property additions, including the impact of acquisitions	3	5
Corporate
Segment Reporting Information [Line Items]
Assets employed	935		$ 1,508
Total property additions, including the impact of acquisitions	4	3
Property additions through acquisitions	$ 0	$ 0