Investments - Additional Information (Detail) - USD ($)		3 Months Ended	9 Months Ended
	Sep. 15, 2024	Dec. 31, 2022	Sep. 30, 2024	Sep. 30, 2023
Alcoa Corporation [Member]
Schedule Of Equity Method Investments [Line Items]
Charges recorded		$ 21,000,000	$ 62,000,000
Alcoa Corporation [Member] | Other Nonoperating Income Expense [Member]
Schedule Of Equity Method Investments [Line Items]
Adjustment recorded				$ 41,000,000
ELYSIS TM Limited Partnership [Member]
Schedule Of Equity Method Investments [Line Items]
Basis in investment, due to share of losses			0	$ 0
Unrecognized losses			$ 66,000,000
Saudi Arabia Joint Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Percentage of joint venture ownership interest sold	25.10%
Sale of ownership interest under agreement exchange for issuance shares	85,977,547
Sale of ownership interest under agreement exchange for cash	$ 150,000,000