Property Sale (Details) - Chicago property and easements - CAD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from exchanged property and construction easements		$ 103
Cash proceeds from properties and easements		61
Property assets, Fair value acquired		42
Gain on exchange of properties and easements	$ 5	50	$ 9
Gain on exchange of property and easements, after tax		38
Deferred gain on exchange of property and easements		$ 53

Gain (Loss) on Sale of Properties, after tax

No definition available.

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- Definition

Amount of proceeds received from sale of property (investing) and land easements (operating)

+ References

No definition available.

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- Definition

Amount of gain on the sale of property that does not qualify for gain recognition as of the balance sheet date.

+ References

No definition available.

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- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The amount of fixed assets that an Entity acquires in a noncash (or part noncash) acquisition. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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- Definition

Amount of noncash consideration received for selling an asset or business through a noncash (or part noncash) transaction.

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