Other Financial Information - Additional Information (Detail) - USD ($) $ in Millions |
6 Months Ended | |
|---|---|---|
Jun. 30, 2026 |
Dec. 31, 2025 |
|
| Other Non Operating Income Expense [Line Items] | ||
| Supplier invoices outstanding | $ 113 | $ 157 |
| San Ciprián Smelter [Member] | ||
| Other Non Operating Income Expense [Line Items] | ||
| Restricted cash available for capital improvments | $ 75 | |
| Minimum [Member] | ||
| Other Non Operating Income Expense [Line Items] | ||
| Payment terms | 50 days | |
| Maximum [Member] | ||
| Other Non Operating Income Expense [Line Items] | ||
| Payment terms | 110 days |