Contingencies and Commitments (Details) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Dec. 31, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($) location	Jun. 26, 2020 USD ($) derivative entity
Loss Contingencies [Line Items]
Number of cleanup locations | location			30
Remediation reserve balance	$ 15	$ 15	$ 15
Remediation reserve balance, classified as a current liability	6	7	7
Payments related to remediation expenses applied against the reserve (less than)		1
Guarantees of third party related to project financing		11	11
Combined fair value of guarantees	6	6	6
Coverage limit	80
Total amount committed under outstanding surety bonds		43	43
Surety bonds, amount outstanding		22	22
Bank Loan Obligations
Loss Contingencies [Line Items]
Letters of credit, total amount		123	123
Other Noncurrent Liabilities and Deferred Credits | Separation Agreement
Loss Contingencies [Line Items]
Guarantees of third party related to project financing	$ 1,406	1,406	1,406
Lehman Brothers International (Europe) (“LBIE”) Claims
Loss Contingencies [Line Items]
Number of entities | entity				2
Number of derivative transactions | derivative				2
Estimate of claim				$ 64
Amount reserved		65	65
Alcoa Corporation Workers Compensation Claims
Loss Contingencies [Line Items]
Letters of credit, total amount outstanding		53	53
Arconic Corporation Environmental Obligations
Loss Contingencies [Line Items]
Letters of credit, total amount outstanding		$ 17	$ 17
Maximum | Recurring Costs of Managing Hazardous Substances and Environmental Programs
Loss Contingencies [Line Items]
Percentage of cost of goods sold (percent)			1.00%