Segments - Schedule of Consolidated Earnings from Continuing Operations Before Income Tax Expense (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Segment Revenues	$ 1,353	$ 1,251
Labor and benefits expense	198	197
Raw materials expense	82	84
Depreciation, depletion and amortization expense	144	117
Energy expense	72	74
External freight expense	78	72
Other costs of revenues	444	435
Selling, general and administrative expenses	130	118
Acquisition, divestiture and integration expenses	2	20
Other operating expense (income), net	9	(1,287)
Segment Earnings (Loss) from Operations	194	1,421
Interest expense	56	40
Other nonoperating income, net	(10)	(33)
Earnings before income tax expense	148	1,414
Operating Segments | East Group
Segment Reporting Information [Line Items]
Segment Revenues	599	526
Labor and benefits expense	92	88
Raw materials expense	1	0
Depreciation, depletion and amortization expense	72	50
Energy expense	31	31
External freight expense	20	20
Other costs of revenues	189	177
Selling, general and administrative expenses	42	34
Acquisition, divestiture and integration expenses	0	0
Other operating expense (income), net	0	(2)
Segment Earnings (Loss) from Operations	152	128
Operating Segments | West Group
Segment Reporting Information [Line Items]
Segment Revenues	667	644
Labor and benefits expense	95	99
Raw materials expense	76	80
Depreciation, depletion and amortization expense	67	63
Energy expense	32	34
External freight expense	51	44
Other costs of revenues	242	236
Selling, general and administrative expenses	51	48
Acquisition, divestiture and integration expenses	0	16
Other operating expense (income), net	4	(1,275)
Segment Earnings (Loss) from Operations	49	1,299
Operating Segments | Magnesia Specialties
Segment Reporting Information [Line Items]
Segment Revenues	87	81
Labor and benefits expense	11	10
Raw materials expense	5	4
Depreciation, depletion and amortization expense	4	3
Energy expense	9	9
External freight expense	7	8
Other costs of revenues	13	18
Selling, general and administrative expenses	5	5
Acquisition, divestiture and integration expenses	0	0
Other operating expense (income), net	0	0
Segment Earnings (Loss) from Operations	33	24
Operating Segments | Reportable Segments
Segment Reporting Information [Line Items]
Segment Revenues	1,353	1,251
Labor and benefits expense	198	197
Raw materials expense	82	84
Depreciation, depletion and amortization expense	143	116
Energy expense	72	74
External freight expense	78	72
Other costs of revenues	444	431
Selling, general and administrative expenses	98	87
Acquisition, divestiture and integration expenses	0	16
Other operating expense (income), net	4	(1,277)
Segment Earnings (Loss) from Operations	234	1,451
Corporate
Segment Reporting Information [Line Items]
Segment Revenues	0	0
Labor and benefits expense	0	0
Raw materials expense	0	0
Depreciation, depletion and amortization expense	1	1
Energy expense	0	0
External freight expense	0	0
Other costs of revenues	0	4
Selling, general and administrative expenses	32	31
Acquisition, divestiture and integration expenses	2	4
Other operating expense (income), net	5	(10)
Segment Earnings (Loss) from Operations	$ (40)	$ (30)