Supplementary Information (Net Change in Non-Cash Working Capital) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Supplemental Cash Flow Elements [Abstract] | ||||
| Accounts receivable and accrued revenues | $ 216 | $ 130 | $ 47 | $ 72 |
| Accounts payable and accrued liabilities | 207 | (24) | 200 | (125) |
| Current portion of operating lease liabilities | (24) | 6 | (12) | 26 |
| Income tax receivable and payable | (19) | (1) | (24) | 18 |
| Net change in non-cash working capital | $ 380 | $ 111 | $ 211 | $ (9) |