Other Financial Information - Schedule of Other Noncurrent Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Other Financial Information [Abstract]
Value added tax credits	$ 257	$ 213
Prepaid gas transmission contract	229	278
Deferred mining costs, net	227	184
Gas supply prepayment	213	225
Goodwill	145	142
Prepaid pension benefit	139	128
IRA Section 45X credit	115	71
Noncurrent restricted cash	68	53
Intangibles, net	34	36
Noncurrent prepaid tax asset	0	66
Other	111	101
Other assets, noncurrent, total	$ 1,538	$ 1,497