Other Long-Term Liabilities - Asset Retirement Obligations (Details) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Reconciliation Of Changes In Provision For Decommissioning Restoration And Rehabilitation Costs [Roll Forward]
Balance – beginning of year	$ 8,607	$ 7,690	$ 6,908
Balance – end of year	9,743	8,607	7,690
Total provision for decommissioning, restoration and rehabilitation costs	9,743	8,607	7,690
Less: current portion	956	787	634
Non-current asset retirement obligation	8,787	7,820	7,056
Udniscounted and uninflated asset retirement obligations	17,600	16,100	15,500
Provision for decommissioning, restoration and rehabilitation costs
Reconciliation Of Changes In Provision For Decommissioning Restoration And Rehabilitation Costs [Roll Forward]
Liabilities incurred	34	28	25
Liabilities acquired, net	489	171	0
Liabilities settled	(771)	(646)	(509)
Asset retirement obligation accretion	380	389	366
Revision of cost, inflation and timing estimates	1,233	417	621
Change in discount rates	(129)	419	314
Foreign exchange adjustments	$ (100)	$ 139	$ (35)

Decommissioning Restoration And Uninflated, Gross Asset Retirement Obligations

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- Definition

Increase (Decrease) Through Change In Cost Inflation and Timing Estimates

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- Definition

Reconciliation Of Changes In Provision For Decommissioning Restoration And Rehabilitation Costs [Roll Forward]

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No definition available.

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- Definition

The increase in other provisions resulting from acquisitions through business combinations. [Refer: Total for all business combinations [member]; Other provisions]

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The increase (decrease) in other provisions resulting from a change in discount rate. [Refer: Other provisions]

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- Definition

The increase (decrease) in other provisions resulting from foreign currency exchange rate changes on provisions measured in a currency different from the entity's presentation currency. [Refer: Other provisions]

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The increase in other provisions through adjustments arising from the passage of time. [Refer: Other provisions]

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- Definition

The amount of non-current provision for decommissioning, restoration and rehabilitation costs. [Refer: Provision for decommissioning, restoration and rehabilitation costs]

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The amount recognised for new other provisions. [Refer: Other provisions]

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The amount of provision for costs related to decommissioning, restoration and rehabilitation. [Refer: Other provisions]

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The amount used (ie incurred and charged against the provision) for other provisions. [Refer: Other provisions]

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The amount of current provision for decommissioning, restoration and rehabilitation costs. [Refer: Provision for decommissioning, restoration and rehabilitation costs]

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