Income Taxes (Reconciliation of Income Tax Expense) (Details) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income tax expense reconciliation
Canadian statutory federal tax rate	15.00%	15.00%	15.00%
Income tax expense at the Canadian statutory federal tax rate	$ 682	$ 814	$ 852
Income tax expense resulting from:
Provincial and foreign taxes	416	551	535
Income tax adjustments due to rate enactments and tax law changes	(141)	(112)	0
Gain on disposals	(1)	(6)	(51)
Other	26	(34)	18
Income tax expense	982	1,213	1,354
Net cash payments for income taxes	$ 353	$ 822	$ 776

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The portion of the difference, between total income tax expense (benefit) as reported in the Income Statement for the period and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to provincial and foreign federal, state and local income tax expense (benefit).

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, attributable to increase (decrease) in the income tax rates.

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Amount of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rates to pretax income (loss) from continuing operations, attributable to disposition of asset. Includes, but is not limited to, intra-entity transfer of asset other than inventory.

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

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