v3.25.2
Contingencies, Commitments and Other Liabilities (Details)
€ in Millions, $ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Jul. 23, 2024
USD ($)
Jul. 23, 2024
EUR (€)
Mar. 31, 2023
USD ($)
Mar. 31, 2023
EUR (€)
Jun. 30, 2025
USD ($)
Dec. 31, 2024
USD ($)
Jun. 30, 2025
USD ($)
location
Dec. 31, 2023
USD ($)
Dec. 31, 2023
EUR (€)
Jul. 23, 2024
EUR (€)
Loss Contingencies [Line Items]                    
Number of cleanup locations | location             30      
Remediation reserve balance         $ 16 $ 19 $ 16      
Remediation reserve balance, classified as a current liability         7 10 7      
Payments related to remediation expenses applied against the reserve (less than in second quarter)         1   3      
Guarantees of third party related to project financing         6   6      
Combined fair value of guarantees         5 6 $ 5      
Indemnification of liability (as a percent)             50.00%      
Coverage limit           $ 80        
Total amount committed under outstanding surety bonds         45   $ 45      
Surety bonds, amount outstanding         $ 20   $ 20      
Termination notice period (in days)             30 days      
Payment timing (in days)         120 days   120 days      
Supplier Finance Program, Obligation, Current, Statement of Financial Position [Extensible Enumeration]         Accounts payable, trade (P) Accounts payable, trade (P) Accounts payable, trade (P)      
Supplier invoices subject to future payment         $ 295 $ 268 $ 295      
Letter of Credit                    
Loss Contingencies [Line Items]                    
Maximum borrowing capacity         84   84      
Other Noncurrent Liabilities and Deferred Credits | Separation Agreement                    
Loss Contingencies [Line Items]                    
Guarantees of third party related to project financing         1,121 $ 1,121 $ 1,121      
Foreign Tax Authority | Ministry of the Economy, Finance and Industry, France | Tax Years 2010 Through 2012                    
Loss Contingencies [Line Items]                    
Income tax assessment, estimate of possible loss     $ 17 € 16            
Income tax assessment, amount of penalties cancelled $ 7                 € 7
Income tax reserve               $ 21 € 19  
Recurring Costs of Managing Hazardous Substances and Environmental Programs                    
Loss Contingencies [Line Items]                    
Percentage of cost of goods sold (as a percent)             1.00%      
Income Tax and Interest | Foreign Tax Authority | Ministry of the Economy, Finance and Industry, France | Tax Years 2010 Through 2012                    
Loss Contingencies [Line Items]                    
Income tax assessment, estimate of possible loss $ 10 € 9 10 9            
Income Tax Penalties | Foreign Tax Authority | Ministry of the Economy, Finance and Industry, France | Tax Years 2010 Through 2012                    
Loss Contingencies [Line Items]                    
Income tax assessment, estimate of possible loss     7 7            
Additional Interest on Income Tax | Foreign Tax Authority | Ministry of the Economy, Finance and Industry, France | Tax Years 2010 Through 2012                    
Loss Contingencies [Line Items]                    
Income tax assessment, estimate of possible loss     $ 2 € 2            
Alcoa Corporation Workers Compensation Claims                    
Loss Contingencies [Line Items]                    
Letters of credit, total amount outstanding         48   $ 48      
Arconic Corporation Environmental Obligations                    
Loss Contingencies [Line Items]                    
Letters of credit, total amount outstanding         $ 9   $ 9