Balance Sheet and Cash Flow Supplemental Information - Schedule of Additional Supplemental Cash Flow Information (Details) - USD ($) $ in Millions |
6 Months Ended | 12 Months Ended | |
|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Dec. 31, 2025 |
|
| Supplemental non cash information: | |||
| Operating activities - Chloride slag inventory purchases made from AMIC (including VAT) | $ 0 | $ 11 | |
| Operating activities - MGT sales made to AMIC | 3 | 3 | |
| Investing activities - In-kind receipt of AMIC loan repayment | 0 | 11 | |
| Financing activities - Initial commercial insurance premium financing agreement | 0 | 1 | |
| Financing activities - Repayment of MGT loan | 3 | $ 3 | |
| Capital expenditures acquired but not yet paid | $ 39 | $ 44 | |