Summary of significant accounting policies - Narrative (Detail) |
12 Months Ended |
|---|---|
Dec. 31, 2025 | |
| Kearl Joint Venture | |
| Significant Accounting Policies [Line Items] | |
| Undivided interest in oil and gas activities | 70.96% |
| Syncrude Joint Venture | |
| Significant Accounting Policies [Line Items] | |
| Undivided interest in oil and gas activities | 25.00% |
| Refinery And Chemical Process | |
| Significant Accounting Policies [Line Items] | |
| Property plant and equipment, useful life | 25 years |
| Maximum | Mining Heavy Equipment | |
| Significant Accounting Policies [Line Items] | |
| Property plant and equipment, useful life | 15 years |
| Maximum | Ore Processing Plant Assets | |
| Significant Accounting Policies [Line Items] | |
| Property plant and equipment, useful life | 50 years |